hftest.py: Run 'exit' command after running all tests

So as to automate running tests on Android boards, hftest.py should call
the 'exit' command when it's finished running tests in the current test
suite. The board will boot into the Android bootloader and will be ready
to accept the next initrd.

Change-Id: I520931f11368e31aa188a4b94f5cb914b13d3b84
1 file changed