This commit:
- Introduces a new `InParallelOpInterface`, along with the
`ParallelCombiningOpInterface`, represent the parallel updating
operations we have in a parallel loop of `scf.forall`.
- Change the name of `ParallelCombiningOpInterface` to
`InParallelOpInterface` as the naming was quite confusing.
- `ParallelCombiningOpInterface` now is used to generalize operations
that insert into shared tensors within parallel combining regions.
Previously, only `tensor.parallel_insert_slice` was supported directly
in `scf.InParallelOp` regions.
- `tensor.parallel_insert_slice` now implements
`ParallelCombiningOpInterface`.

This change enables future extensions to support additional parallel
combining operations beyond `tensor.parallel_insert_slice`, which have
different update semantics, so the `in_parallel` region can correctly
and safely represent these kinds of operation without potential mistakes
such as races.

Author credits: @qedawkins

These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

This is necessary to run the new buffer deallocation pipeline as part of
the sparse compiler pipeline.

This is necessary to support deallocation of IR with gpu.launch
operations because it does not implement the RegionBranchOpInterface.
Implementing the interface would require it to support regions with
unstructured control flow and produced arguments/results.

The scf.forall.in_parallel terminator operation has a nested graph region with the NoTerminator trait. Such regions are not supported by the default implementations. Therefore, this commit adds a specialized implementation for
this operation which only covers the case where the nested region is empty.
This is because after bufferization, ops like tensor.parallel_insert_slice were already converted to memref operations residing int the scf.forall only and the nested region of scf.forall.in_parallel ends up empty.

This reverts commit 1356e853d47723c1be6eee2368d95c514a1816d1.

This caused problems in downstream projects. We are reverting to give
them more time for integration.

The scf.forall.in_parallel terminator operation has a nested graph region with
the NoTerminator trait. Such regions are not supported by the default
implementations. Therefore, this commit adds a specialized implementation for
this operation which only covers the case where the nested region is empty.
This is because after bufferization, ops like tensor.parallel_insert_slice were
already converted to memref operations residing int the scf.forall only and the
nested region of scf.forall.in_parallel ends up empty.

Reviewed By: springerm

Differential Revision: https://reviews.llvm.org/D158979