[mlir][Linalg] Move patterns to remove dead arguments and results out of canonicalization.

The patterns to remove dead arguments and results of `linalg.generic`
operations are not necessarily canonicalizations. Instead a new entry
point `populateEraseUnusedOperandsAndResults` is added to allow using
these patterns when needed. The transformations that rely on this
pattern for cleanup now include these patterns explicitly.

Differential Revision: https://reviews.llvm.org/D138085