Duncan Coutts authored May 30, 2018 and Alexis Williams committed Jul 14, 2018

On Windows, file locks held by programs we run (in this case VCSs) are
not always released prior to completing process termination! Obviously
this is total madness since we can't know what files the child process
had locks on, and so we cannot wait for those locks to be released.

https://msdn.microsoft.com/en-us/library/windows/desktop/aa365202.aspx

This means we run into stale locks when trying to delete the test
directory. There is no sane way to wait on those locks being
released, we just have to wait and hope. Lets hope 1 second is enough.