[llvm] GlobalISel: Fix defined register of invariant.start (PR #125664)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,24 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=amdgcn -mcpu=gfx90a -O0 -global-isel=true --stop-after=irtranslator -o - %s | FileCheck %s
+target datalayout = "A5"
----------------
arsenm wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/125664