[clang] [clang][ThreadSafety] Enable late parse for all capabilities, under the experimental flag (PR #212615)

[Jameson Nash via cfe-commits]

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@@ -0,0 +1,83 @@
+// Capability attributes are late parsed under -fexperimental-late-parse-attributes,
+// like guarded_by and pt_guarded_by already were, so they can name a member
+// declared later in the same struct.
+//
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vtjnash wrote:

Yep, those were definitely needed since they caught 2 new bugs

https://github.com/llvm/llvm-project/pull/212615