[clang] Make -frewrite-includes put an endif at the end of the included text (PR #67613)

[Paul T Robinson via cfe-commits]

================
@@ -98,7 +98,7 @@
 // == file2.h
 // REWRITE: #if 0
 // REWRITE: #include "file2.h"
-// REWRITE: #endif
+// REWRITE: #else /* file2.h expanded
----------------
pogo59 wrote:

Yes it does, but the point here is simply to identify that this is the correct `#else`. The Preprocessor tests look for the full comment.

https://github.com/llvm/llvm-project/pull/67613