[globalisel][tablegen] Partially fix compile-time regressions by converting...

[globalisel][tablegen] Partially fix compile-time regressions by converting matcher to state-machine(s)

Summary:
Replace the matcher if-statements for each rule with a state-machine. This
significantly reduces compile time, memory allocations, and cumulative memory
allocation when compiling AArch64InstructionSelector.cpp.o after r303259 is
recommitted.

The following patches will expand on this further to fully fix the regressions.

Reviewers: rovka, ab, t.p.northover, qcolombet, aditya_nandakumar

Reviewed By: ab

Subscribers: vitalybuka, aemerson, javed.absar, igorb, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D33758

llvm-svn: 307079