[mlir][nfc] Update vectorize-tensor-extract.mlir (2/N) (#119080)
Tests in "vectorize-tensor-extract.mlir" are inconsistent and would
benefit from refactoring to:
* Clearly categorize tests into "contiguous load," "gather load," and
"scalar load + broadcast" cases, reflecting the structure of
tensor.extract vectorization.
* Unify variable naming (both MLIR and FileCheck).
* Ensure all tests exercise unmasked vectorization (masked vectorization
is covered in "vectorize-tensor-extract-masked.mlir").
* Improve and standardize formatting.
These changes will make it easier to identify the test cases being
exercised and simplify future maintenance or refactoring.
This is patch 2/N in the series; below is a summary of the specific
changes
in this patch.
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Summary of patch 2/N
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Makes all tests re-use the same TD sequence. This TD sequence has been
extracted to a deducted file:
* "td/vectorize-with-patterns.mlir".
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Previous patches:
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* https://github.com/llvm/llvm-project/pull/118977