[GlobalISel][InstructionSelect] Moving Reg Bank Checks forward, perf patch 9

This patch continues a series of patches started by r332907 (reapplied
as r332917).

In this commit we move register bank checks back from epilogue of
every rule matcher to a position locally close to the rest of the
checks for a particular (nested) instruction.

This increases the number of common conditions within 2nd level
groups.

This is expected to decrease time GlobalISel spends in its
InstructionSelect pass by about 2% for an -O0 build as measured on
sqlite3-amalgamation (http://sqlite.org/download.html) targeting
AArch64 (cross-compile on x86).

Reviewers: qcolombet, dsanders, bogner, aemerson, javed.absar

Reviewed By: qcolombet

Subscribers: rovka, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D44700

llvm-svn: 333144