Make gtest for long path names on Windows more resilient in the presence of virus scanners

A virus scanner can keep a file open on Windows, so that a DeleteFile command returns successful, but the file is actually not removed when the call returns. In the gtest for long path names on Windows this can lead to failures when a directory is tried to removed, but the file inside it is still kept by the virus scanner.

Since this is not a error which occurs frequently, a solution is to just wait a few seconds and try again.