[clang-tools-extra] [clang-tidy] Added Conflicting Global Accesses checker (PR #130421)

[Áron Hárnási via cfe-commits]

ConcreteCactus wrote:

Hi Everyone,
I fixed a crash in the ExecutionVisitor. It wasn't checking whether the definition of a class exists before trying to recurse into the destructor.

Can I get a re-review on this PR? I think I addressed most of the comments.

https://github.com/llvm/llvm-project/pull/130421