[WIP] Utility for creating dispatch-based test files from torch-mlir model

[newling]

Example usage

./generate_dispatch_test.sh   my_torch_model.mlir   output_dir   ${iree_build_dir}

Creates a directory containing func.func files in linalg, designed for testing with AIE backend. Example: run on test.mlir in this PR, and observe the 2 files generated in the post_opt directory