[MLIR] Introduce applyOpPatternsAndFold for op local rewrites

Introduce mlir::applyOpPatternsAndFold which applies patterns as well as
any folding only on a specified op (in contrast to
applyPatternsAndFoldGreedily which applies patterns only on the regions
of an op isolated from above).  The caller is made aware of the op being
folded away or erased.

Depends on D77485.

Differential Revision: https://reviews.llvm.org/D77487