https://github.com/llvm/llvm-project/issues/159474

Another try of trying to land
https://github.com/llvm/llvm-project/pull/166382
- Fix some leftover tests checking for specific  errnos
- Guard errno checking tests to not run on the GPU

@michaelrj-google

https://github.com/llvm/llvm-project/issues/159474

Resubmitting https://github.com/llvm/llvm-project/pull/162876 with fixes
as it broke some buildbots:
 - Fix comparisons of integer expressions of different signedness
- Not check for specific errnos in tests, as they might not be available
on all platforms

[#159474](https://github.com/llvm/llvm-project/issues/159474)

- All printf variants set errno and consistently return -1 on error,
instead of returning various predefined error codes
- Return value overflow handling is added

Summary:
This had some leftover references to the old namespace and didn't put
restrict on it.

[libc] Implement vasprintf and asprintf

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Co-authored-by: Izaak Schroeder <izaak.schroeder@gmail.com>