[llvm] [RegisterPressure] Remove dead defs correctly (PR #156576)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,19 @@
+# RUN: llc -mtriple=x86_64-unknown-unknown -run-pass=machine-scheduler -verify-misched -o - %s
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arsenm wrote:

Generate checks. Also this belongs in test/CodeGen/X86 as it's not a mir parser test 

https://github.com/llvm/llvm-project/pull/156576