[llvm] fix a assert on the PR 125883 (PR #135056)

[Simon Pilgrim via llvm-commits]

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@@ -0,0 +1,19 @@
+; RUN: llc < %s -mtriple=riscv32  | FileCheck %s
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RKSimon wrote:

Incorrect filename - prXXXXX.ll is for Problem Reports (a very old name) - which now map to issue numbers - don't use pull request numbers here

https://github.com/llvm/llvm-project/pull/135056