[llvm] [LIT] Add support for `%basename_s` to get base name of source file (PR #110993)

[Rahul Joshi via llvm-commits]

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@@ -535,6 +535,7 @@ TestRunner.py:
  %{fs-tmp-root}          root component of file system paths pointing to the test's temporary directory
  %{fs-sep}               file system path separator
  %t                      temporary file name unique to the test
+ %basename_s             The last path component of %s
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jurahul wrote:

I created: https://github.com/llvm/llvm-project/pull/111062, will start review once checks pass.

https://github.com/llvm/llvm-project/pull/110993