Use JUnitCore to run a list of VogarTest instances

Moved functionality for running tests with a timeout into
VogarTestRunner and added VmIsUnstableException which extends
StoppedByUserException and is used to abort the test run when a
test times out and so leaves the VM in an unstable state.

Bug: 27940141
Change-Id: I99f4c44eaf9c8e4303bdd4def5bd287bf7bdafdb
3 files changed