[Speculation] Add Commit and SaveCommit control paths

[asleix]

This commit updates the way that SpecCommitOp and SpecSaveCommitOp are connected to SpeculatorOp. The commit and commit-like control signals should replicate the actual path that speculative tokens take, and only reach the operations when speculative tokens do.

The changes include:

• Add three methods to the pass driver: routeBranchControlTraversal, prepareAndPlaceCommits, prepareAndPlaceSaveCommits.
• Add inheritBB such that the newly created operations have a BB assigned.
• Add three unit tests. Each of the tests is called with the specific associated JSON file. These files also serve as example of the pass utilization. To run the tests, use ninja check-dynamatic-experimental from your build.

[asleix]

As Lucas suggested, smaller and more meaningful tests proved more useful for verification. The new tests are included and the old ones were removed.

[asleix]

Hi @RamirezLucas! Emmet and I met this afternoon to discuss his comments and we agreed that the PR is now ready to be merged. Thanks a lot!