[clang] Fix preprocessed block comment newline on windows containing extra carriage return (PR #205084)

[Joel E. Denny via cfe-commits]

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@@ -0,0 +1,4 @@
+// RUN: %{to-crlf} %S/Inputs/comment_save_crlf.h > %t.h
+// RUN: %clang_cc1 -E -C -o %t.i %t.h
+// RUN: %{reveal-cr} %t.i | FileCheck %s
+// CHECK-NOT: <CR>
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jdenny-ornl wrote:

Generally, CHECK-NOT is known to cause rotten green tests. Specifically, there's no test anywhere checking that these sed commands ever manage to produce a `<CR>`, right? You might consider adding another RUN line like `%{to-crlf} %S/Inputs/comment_save_crlf.h | %{reveal-cr}` to sanity check that `<CR>` actually appears. 

https://github.com/llvm/llvm-project/pull/205084