[libcxx] [llvm] [RFC][libc++][test] Improves C++ Standard filtering. (PR #89499)

[Joel E. Denny via llvm-commits]

================
@@ -165,11 +165,28 @@ def getSuitableClangTidy(cfg):
         default=lambda cfg: next(
             s for s in reversed(_allStandards) if getStdFlag(cfg, s)
         ),
-        actions=lambda std: [
+        actions=lambda std: filter(None, [
----------------
jdenny-ornl wrote:

I prefer this PR's approach.  It keeps lit's implementation simple and defers to individual test suites to specify how they need sorting to be done.

@mordante In the initial PR comment, would you please add a link to your discourse for the sake of people arriving here?

https://github.com/llvm/llvm-project/pull/89499