[clang] Add fine-grained `__has_feature()` cutout (PR #170822)

[via cfe-commits]

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@@ -441,6 +441,9 @@ class LangOptions : public LangOptionsBase {
   SanitizerSet Sanitize;
   /// Is at least one coverage instrumentation type enabled.
   bool SanitizeCoverage = false;
+  /// Set of enabled (undefined behavior) sanitizers that do not cause
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j39m wrote:

Pushing a fixup commit to incorporate...

https://github.com/llvm/llvm-project/pull/170822