[llvm] [NFC][AMDGPU] Pre-commit a test case for `v_pk_mov_b32` in `vgpr-remat.mir` (PR #127715)

[Matt Arsenault via llvm-commits]

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@@ -46,3 +46,50 @@ body: |
     %4.sub1:vreg_96 = COPY %2:vgpr_32
     S_ENDPGM 0, implicit %4
 ...
+
+---
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arsenm wrote:

The test is running with -mcpu=gfx900, which doesn't have v_pk_mov_b32. At one point I was working on making MIR tests less permissive about mismatches, maybe should adjust the target-cpu for the run line 

https://github.com/llvm/llvm-project/pull/127715