PCG serialization, rapidcheck, dtgen, and shape inference

[lockshaw]

Description of changes:

• Move many visitable types over to dtgen
• Add new-style reduction dims and parallel tensor shape
• Add parallel shape inference for a subset of operators
  • Add
  • ReLU
  • Linear
  • Conv2D
  • BatchMM
  • Embedding
  • Repartition
  • Combine
  • Replicate
  • Reduction
• De-template substitutions
• Refactor PCG, ComputationGraph, etc. do be serializable and based on new DataflowGraph abstraction
• Add rapidcheck Arbitrary instances for many types, primarily through moving many types over to dtgen

Note: this PR temporarily breaks substitutions, which will be moved to a follow-up PR to prevent this PR from growing too large

Related Issues:

Supersedes #988

Linked Issues:

• Issue #919

Issues closed by this PR:

• Closes #1276

---

This change is 

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 13.41872% with 4394 lines in your changes missing coverage. Please review.

Project coverage is 18.81%. Comparing base (c97f63f) to head (6230d99).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## repo-refactor #1394 +/- ## ================================================== - Coverage 41.32% 18.81% -22.52% ================================================== Files 181 263 +82 Lines 5265 12631 +7366 Branches 271 0 -271 ================================================== + Hits 2176 2377 +201 - Misses 3089 10254 +7165 ``` | [Flag](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow) | `18.81% <13.41%> (-22.52%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow) | Coverage Δ | | |---|---|---| | [lib/op-attrs/include/op-attrs/dim\_ordered/slice.h](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Finclude%2Fop-attrs%2Fdim_ordered%2Fslice.h&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL2luY2x1ZGUvb3AtYXR0cnMvZGltX29yZGVyZWQvc2xpY2UuaA==) | `100.00% <100.00%> (ø)` | | | [.../op-attrs/include/op-attrs/dim\_ordered/transform.h](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Finclude%2Fop-attrs%2Fdim_ordered%2Ftransform.h&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL2luY2x1ZGUvb3AtYXR0cnMvZGltX29yZGVyZWQvdHJhbnNmb3JtLmg=) | `100.00% <100.00%> (ø)` | | | [lib/op-attrs/include/op-attrs/get\_output\_shapes.h](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Finclude%2Fop-attrs%2Fget_output_shapes.h&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL2luY2x1ZGUvb3AtYXR0cnMvZ2V0X291dHB1dF9zaGFwZXMuaA==) | `0.00% <ø> (ø)` | | | [...p-attrs/src/op-attrs/computation\_graph\_op\_attrs.cc](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Fsrc%2Fop-attrs%2Fcomputation_graph_op_attrs.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL3NyYy9vcC1hdHRycy9jb21wdXRhdGlvbl9ncmFwaF9vcF9hdHRycy5jYw==) | `100.00% <100.00%> (ø)` | | | [...rs/src/op-attrs/ops/conv\_2d/conv\_2d\_input\_shape.cc](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Fsrc%2Fop-attrs%2Fops%2Fconv_2d%2Fconv_2d_input_shape.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL3NyYy9vcC1hdHRycy9vcHMvY29udl8yZC9jb252XzJkX2lucHV0X3NoYXBlLmNj) | `100.00% <100.00%> (ø)` | | | [lib/op-attrs/src/op-attrs/ops/reduction.cc](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Fsrc%2Fop-attrs%2Fops%2Freduction.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL3NyYy9vcC1hdHRycy9vcHMvcmVkdWN0aW9uLmNj) | `100.00% <100.00%> (ø)` | | | [lib/op-attrs/src/op-attrs/ops/repartition.cc](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Fsrc%2Fop-attrs%2Fops%2Frepartition.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL3NyYy9vcC1hdHRycy9vcHMvcmVwYXJ0aXRpb24uY2M=) | `100.00% <100.00%> (ø)` | | | [lib/op-attrs/src/op-attrs/ops/replicate.cc](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Fsrc%2Fop-attrs%2Fops%2Freplicate.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL3NyYy9vcC1hdHRycy9vcHMvcmVwbGljYXRlLmNj) | `100.00% <100.00%> (ø)` | | | [lib/op-attrs/src/op-attrs/ops/batch\_norm.cc](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Fsrc%2Fop-attrs%2Fops%2Fbatch_norm.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL3NyYy9vcC1hdHRycy9vcHMvYmF0Y2hfbm9ybS5jYw==) | `0.00% <0.00%> (ø)` | | | [lib/op-attrs/src/op-attrs/ops/dropout.cc](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree&filepath=lib%2Fop-attrs%2Fsrc%2Fop-attrs%2Fops%2Fdropout.cc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow#diff-bGliL29wLWF0dHJzL3NyYy9vcC1hdHRycy9vcHMvZHJvcG91dC5jYw==) | `0.00% <0.00%> (ø)` | | | ... and [82 more](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow) | | ... and [209 files with indirect coverage changes](https://app.codecov.io/gh/flexflow/FlexFlow/pull/1394/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flexflow)