The script was broken after the change to build to a separate shared
library. Also fixes issues on Windows and cleans up the code. State
comparison is still broken on every test from what I can see.

Bug: angleproject:5530
Change-Id: I23e77e56fadedfb85d7afdb59dddac5558a71a56
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2630232
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>