[clang] [Attributes] Support Attributes being declared as only supporting late parsing when passing an experimental feature flag (PR #88596)

[Yeoul Na via cfe-commits]

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@@ -91,11 +91,24 @@ static StringRef normalizeAttrName(StringRef Name) {
 
 /// isAttributeLateParsed - Return true if the attribute has arguments that
 /// require late parsing.
-static bool isAttributeLateParsed(const IdentifierInfo &II) {
+bool Parser::isAttributeLateParsed(const IdentifierInfo &II) {
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rapidsna wrote:

I think the function also needs some update to make it so that attributes marked as `LateParseAttrExperimentalExt` will fall back to the behavior equivalent to `LateParseAttrStandard`. Currently, it seems that the function will always return `false` for attributes with `LateParseAttrExperimentalExt` when the experimental flag is disabled.

https://github.com/llvm/llvm-project/pull/88596