Use Xvfb in isolated testing only if use_x11 is set (reland)
We don't need a virtual X server for ozone testing, and it is causing
problems running the tests with swarming. This changes all isolate files
to only run Xvfb if use_x11==1 is set in GYP_DEFINES, and merges ozone
with Windows & Mac (none of which need to run their own display server).
BUG=440882
TEST=isolate.py run -s out_ozone/Debug/<various>
TBR=maruel
Review URL: https://codereview.chromium.org/908313004
Cr-Commit-Position: refs/heads/master@{#319919}
15 files changed
