[clang] [clang][analyzer] Add checker 'alpha.core.FixedAddressDereference' (PR #127191)

[Balázs Kéri via cfe-commits]

balazske wrote:

It may cause confusion that "NullDereference" checker checks not only null dereference but undefined pointer and label address  too. Probably these checks (specially label address) can be moved into this checker. (Or add the new check to NullDereference without a new checker?)

https://github.com/llvm/llvm-project/pull/127191