[mlir][Linalg] Make LinalgBaseTilingPattern not delete the original operation.

The LinalgTilingPattern class dervied from the base deletes the
original operation. This allows for the use case where the more
transformations are necessary on the original operation after
tiling. In such cases the pattern can derive from
LinalgBaseTilingPattern instead of LinalgTilingPattern.

Differential Revision: https://reviews.llvm.org/D87308