[clang] Update GoogleTest to v1.14.0 (PR #65823)

[Justin Bogner via cfe-commits]

bogner wrote:

I'm seeing some unused functions in files that haven't been changed in years, which I'm guessing come from this update - did the new googletest change how custom output works?
```
llvm/unittests/Support/JSONTest.cpp:490:27: error: unused function 'operator<<' [-Werror,-Wunused-function]
inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
                          ^
1 error generated.
```
I guess we can just delete this function, but I'm not sure if it means we've degraded the error messages for these tests or anything like that.

https://github.com/llvm/llvm-project/pull/65823