[llvm] [Dexter] Fix test failures on greendragon (PR #66299)

[Adrian Prantl via llvm-commits]

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@@ -217,6 +217,8 @@ def _run_test(self, test_name):
         """
         try:
             if self.context.options.binary:
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adrian-prantl wrote:

Is there a way to check for the darwin platform so this doesn't run on linux?
If not, this will still work fine.

Can you add a comment here explaining why this is needed (i.e., that the dsym contains the debug info)?

https://github.com/llvm/llvm-project/pull/66299