[mlir] relax value handle updates when operation is replaced

The initial implementaiton of value handle update when the payload
operation defining the values associated with value handles was being
replaced required the replacement operation to have the same number of
results. This is not strictly necessary. The replacement operation may
have more results, or less results provided that there are no handles to
the results that have no equivalent in the replacement op.

Reviewed By: springerm

Differential Revision: https://reviews.llvm.org/D145254