[MCA] Allow mca::Instruction-s to be recycled and reused

This patch introduces a new feature that allows InstrBuilder to reuse
mca::Instruction recycled from IncrementalSourceMgr. This significantly
reduces the memory footprint.
Note that we're only recycling instructions that have static InstrDesc
and no variadic operands.

Differential Revision: https://reviews.llvm.org/D127084