Reapply "[clang] Introduce [[clang::lifetime_capture_by(X)]] (#115823) Fix compile time regression and memory leak In the previous change, we saw: - Memory leak: https://lab.llvm.org/buildbot/#/builders/169/builds/5193 - 0.5% Compile time regression [link](https://llvm-compile-time-tracker.com/compare.php?from=4a68e4cbd2423dcacada8162ab7c4bb8d7f7e2cf&to=8c4331c1abeb33eabf3cdbefa7f2b6e0540e7f4f&stat=instructions:u) For compile time regression, we make the Param->Idx `StringMap` for **all** functions. This `StringMap` is expensive and should not be computed when none of the params are annotated with `[[clang::lifetime_capture_by(X)]]`. For the memory leak, the small vectors used in Attribute are not destroyed because the attributes are allocated through ASTContext's allocator. We therefore need a raw array in this case.
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