[mlir] Move `linalg.tensor_expand/collapse_shape` to TensorDialect.

RFC: https://llvm.discourse.group/t/rfc-reshape-ops-restructuring/3310

linalg.fill gets a canonicalizer, because `FoldFillWithTensorReshape` cannot be moved to tensorops (it uses linalg::FillOp inside). Before it was listed as a canonicalization pattern for the reshape operations, now it became a canonicalization for FillOp.

Differential Revision: https://reviews.llvm.org/D115502