Tests are queued retaining the order of testing variants and test suites. This reorders the variants and suites to make sure the slowest run first.

Currently the debugger suite contains the slowest tests.

BUG=v8:5861
TBR=jochen@chromium.org,yangguo@chromium.org,jkummerow@chromium.org

Change-Id: Idae349b5e6db2540c6181f9b5e2ffb689733846e
Reviewed-on: https://chromium-review.googlesource.com/439311Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43046}