[mlir] Add apply_patterns.linalg.pad_vectorization TD Op (#112504)

This PR simply wraps `populatePadOpVectorizationPatterns` into a new
Transform Dialect Op: `apply_patterns.linalg.pad_vectorization`.

This change makes it possible to run (and test) the corresponding
patterns _without_:

  `transform.structured.vectorize_children_and_apply_patterns`.

Note that the Op above only supports non-masked vectorisation (i.e. when
the inputs are static), so, effectively, only fixed-width vectorisation
(as opposed to scalable vectorisation). As such, this change is required
to construct vectorization pipelines for tensor.pad targeting scalable
vectors.

To test the new Op and the corresponding patterns, I added
"vectorization-pad-patterns.mlir" - most tests have been extracted from
"vectorization-with-patterns.mlir".

0 files changed, 0 insertions, 0 deletions