[llvm] [FileCheck] Fix parsing empty global and pseudo variable names (PR #83667)

[Fangrui Song via llvm-commits]

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@@ -0,0 +1,32 @@
+a
+
+; RUN: not FileCheck -color=0 -input-file %s %s 2>&1 | \
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MaskRay wrote:

I disagree. There are many `CHECK.*error:` tests and they don't use `-color=0` at all.

https://github.com/llvm/llvm-project/pull/83667