[clang] [analyzer] Fix crash on dereference invalid return value of getAdjustedParameterIndex() (PR #83585)

[Balazs Benics via cfe-commits]

https://github.com/steakhal commented:

The patch looks a lot better this way. Thanks!

I'd recommend adding this test to the existing `clang/test/Analysis/cxx2b-deducing-this.cpp` test file to have all deducing this testcases at a common place.

https://github.com/llvm/llvm-project/pull/83585