[clang] [clang][analyzer] Add test cases for CTU-import failures (PR #188524)

[Balázs Kéri via cfe-commits]

balazske wrote:

I like adding these tests and improve error reporting. One issue with these tests can be that if the import "silently fails" we can not verify if there was really the expected type of error (or no error), but this is less important. (But I would like more if these cases are somehow shown to the user.) Probably the rename and move part of this change can be moved to another PR. The new failure tests can be moved again to new subdirectory (or have a common name).

https://github.com/llvm/llvm-project/pull/188524