[llvm] [AArch64] Re-enable rematerialization for streaming-mode-changing functions. (PR #83235)

[Paul Walker via llvm-commits]

================
@@ -443,6 +443,9 @@ AArch64RegisterInfo::getStrictlyReservedRegs(const MachineFunction &MF) const {
       Reserved.set(SubReg);
   }
 
+  // VG cannot be allocated
+  Reserved.set(AArch64::VG);
----------------
paulwalker-arm wrote:

Should this be protected by `hasSVEorSME`? or does the definition of `MSRpstatePseudo` precluded that.

https://github.com/llvm/llvm-project/pull/83235