[mlir][test] Fix -Wsign-compare in TestDialect.cpp (NFC)

llvm-project/mlir/test/lib/Dialect/Test/TestDialect.cpp:597:31:
error: comparison of integers of different signs: 'size_t' (aka 'unsigned long') and 'int64_t' (aka 'long') [-Werror,-Wsign-compare]
  if (getVarOperands().size() != expectedNumOperands)
      ~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~~~~~
1 error generated.
GitOrigin-RevId: cce026bf8f7dcf5aa402a6da20f0d4da56aee8b5
1 file changed
tree: f3518c5f55c28896d6ce46815057856a8cf9778c
  1. benchmark/
  2. cmake/
  3. docs/
  4. examples/
  5. include/
  6. lib/
  7. python/
  8. test/
  9. tools/
  10. unittests/
  11. utils/
  12. .clang-format
  13. .clang-tidy
  14. CMakeLists.txt
  15. LICENSE.TXT
  16. README.md
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Multi-Level Intermediate Representation

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