Instead of installing all dependencies manually, the script should run
with the dependencies specified by the wheels listed in the VPYTHON
section of the header comments.

Bug: angleproject:3415
Change-Id: Ie969ada3ec2550ae2a809164b01930e1590d5db1
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1593736
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>