i#2041: remove flaky test from client.file_io
i#2041: remove flaky test from client.file_io

Removes the comparisons of dr_get_time() fields with localtime() on UNIX and
GetSystemTime() on Windows as it's just too complex to easily compare
in a non-flaky manner.

Fixes #2041

Review-URL: https://codereview.appspot.com/315990043

AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio