[clang] [analyzer] Match dangling subobjects by their base region in DanglingPtrDeref (PR #211552)

[Gábor Horváth via cfe-commits]

https://github.com/Xazax-hun approved this pull request.

LG, I think we could add some more tests though. 

https://github.com/llvm/llvm-project/pull/211552