This pull request creates a new source file for test utils, and moves GetTempPath() from util to testutil.
This is because per the above issues, GetTempPath() is insecure and has unchecked error conditions, making it unsuitable for use in production code. GetTempPath() is only used in the unit tests and not used anywhere in the main code, so it would be a good idea to move this to the test suite so that no one tries to use this in the future and it's not mixed with production code.