RegReAssign hits an unreachable on AArch64 as it is a pass (conceptually) specific to X86. - Add a guard to RegReAssign for non-X86 - Update unsupported-passes.test
RegReAssign hits an unreachable on AArch64 as it is a pass (conceptually) specific to X86. - Add a guard to RegReAssign for non-X86 - Update unsupported-passes.test