BUG: reduce the size of test driver

The list of files for the test driver was not cleared after a new
number was created. The cased each test driver to have all prior
tests. Not the drivers are correctly split.

Change-Id: Ice249a980c49e49f793ba69ee05f6949e113fb96
Merge branch 'FixTestDriverSplit' into release

Change-Id: I40f70838f1bb4f63479d0424dd32641c6743c4a9