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

[Balázs Kéri via cfe-commits]

balazske wrote:

The checker is alpha because there are known problems with it which I plan to fix later.
A problem is with the bugpath messages where a constant pointer was assumed to be a null pointer but after this checker (or even before it?) this is not true.

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