[clang] [Sema] Add lambda decltype((x)) semantics to blocks (#207355) (PR #207583)

[Bohdan Yehorov via cfe-commits]

BohdanYehorov wrote:

@ahatanak I verified: this patch doesn't change behavior for variables in captured regions, including OpenMP, and for variables marked `__block`. The method `getCapturedDeclRefType` doesn't make the type const in blocks (for `__block`-qualified variables), in lambdas by reference, and in captured regions but makes the type const in blocks (for non-`__block-qualified` variables) and in lambdas by value. So, patch changes behavior only for non-`__block`-qualified variables in blocks.

https://github.com/llvm/llvm-project/pull/207583