[llvm] [llvm-symbolizer] Improve error messages for filter symbolization failure (PR #114649)

[James Henderson via llvm-commits]

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@@ -0,0 +1,10 @@
+RUN: split-file %s %t
+RUN: llvm-symbolizer --filter-markup < %t/log > /dev/null 2> %t.err
+RUN: FileCheck %s -input-file=%t.err --match-full-lines --strict-whitespace
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jh7370 wrote:

```suggestion
RUN: FileCheck %s --input-file=%t.err --match-full-lines --strict-whitespace
```
Nit for consistency with the rest of the line.

https://github.com/llvm/llvm-project/pull/114649