Ensure we have root permissions to run JDWP tests on target

We need to "adb root" the device to remount the system partition and
synchronize files before running the JDWP tests on the device.

Change-Id: I0dc847ff9f9b0073b72edc25180d980dca1367dd
Merge "Ensure we have root permissions to run JDWP tests on target"