[NewPM] Fix print-changed-dot-cfg failure (#88351)

Fix failure in #80946.

Author: paperchalice

llvm/test/Other/ChangePrinters/DotCfg/print-changed-dot-cfg.mir

@@ -1,7 +1,7 @@
 # REQUIRES: x86-registered-target
 # Simple functionality check.
 # RUN: rm -rf %t && mkdir -p %t
-# RUN: llc -filetype=null -print-changed=dot-cfg -passes=no-op-machine-function -dot-cfg-dir=%t %s
+# RUN: llc -mtriple=x86_64-pc-linux-gnu -filetype=null -print-changed=dot-cfg -passes=no-op-machine-function -dot-cfg-dir=%t %s
 # RUN: ls %t/*.pdf %t/passes.html | count 3
 
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