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

[Alexander Richardson 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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arichardson wrote:

How much are these features used? I think the naming is somewhat ambiguous: it could mean "LLVM built with sanitizer X" (which is the meaning of that flag) but I could also read it as "default to building with sanitizer x enabled" or even "<sanitizer> is supported on the current target". Maybe an explicit `built-with-<sanitizer>` or `llvm-instrumented-with-<sanitizer>` would be better?

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