[llvm] [AMDGPU] Remove some Wave64 checks for GFX10+ MC tests (NFC) (PR #100971)

[Matt Arsenault via llvm-commits]

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@@ -1,5 +1,4 @@
-// RUN: llvm-mc -triple=amdgcn -mcpu=gfx1200 -mattr=+wavefrontsize32 -show-encoding %s | FileCheck --check-prefixes=GFX12 %s
-// RUN: llvm-mc -triple=amdgcn -mcpu=gfx1200 -mattr=+wavefrontsize64 -show-encoding %s | FileCheck --check-prefixes=GFX12 %s
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arsenm wrote:

This is losing test coverage 

https://github.com/llvm/llvm-project/pull/100971