- create testcase subclass for each test
- move get_command, get_source from suite to test
- promises-aplus tests are broken
- moving expected outcomes etc. is still in progress

Bug: v8:6917
Cq-Include-Trybots: master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: I006e64ecf51dda95c41dff88c68b24f17a638566
Reviewed-on: https://chromium-review.googlesource.com/798331
Commit-Queue: Michał Majewski <majeski@google.com>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50065}