[AMDGPU] Pre-commit test for wait between agpr & vgpr

Due to a typo of 256 to 226, the SIInsertWaitcnt pass thinks
several registers are aliased from a waitcnt PoV including vgpr226
and agpr0, vgpr227 and agpr1...

This is a test of the behavior.
NFC.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D119750