Add control for the ignition test suites. This will be
followed by a change on the infra side that targets the
ignition set instead of the hardcoded mjsunit.
After that, cctest can be enabled in a separate CL. This CL
already includes the logic for running cctest for ignition
on swarming.
BUG=v8:4280
LOG=N
Review URL: https://codereview.chromium.org/1559943002
Cr-Commit-Position: refs/heads/master@{#33089}
