[clang] [clang] Deduplicate the logic that only warns once when stack is almost full (PR #112371)

[Ilya Biryukov via cfe-commits]

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@@ -1183,7 +1181,7 @@ class Sema final : public SemaBase {
   std::optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;
   bool WarnedDarwinSDKInfoMissing = false;
 
-  bool WarnedStackExhausted = false;
+  SingleWarningStackAwareExecutor StackAwareExecutor;
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ilya-biryukov wrote:

Makes sense to keep this as an action for the future. Sharing the logic makes sense, though.

Should we file an issue on GitHub and/or add a FIXME to the code that we might want to share a single instance Sema and CodeGen in the future?

https://github.com/llvm/llvm-project/pull/112371