[llvm] [llvm][lit] Add tsan feature when enabled (PR #94573)

[Keith Smiley via llvm-commits]

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@@ -131,6 +131,8 @@ def __init__(self, lit_config, config):
             features.add("msan")
         if "undefined" in sanitizers:
             features.add("ubsan")
+        if "thread" in sanitizers:
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keith wrote:

looks like ~200 uses today. I think unless we renamed all of them people would be surprised if tsan was an outlier here

https://github.com/llvm/llvm-project/pull/94573