[clang] [clang-format] Fix a regression in dumping the config (PR #80628)

[Owen Pan via cfe-commits]

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@@ -1,5 +1,8 @@
+// RUN: clang-format -assume-filename=foo.m -dump-config | FileCheck %s
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owenca wrote:

Yes, because it wouldn't make a difference before and after the patch. I don't think we can use lit to test that behavior (i.e., not waiting for an EOF) of clang-format in the terminal.

https://github.com/llvm/llvm-project/pull/80628