Add a commandline server test runner (#789)
Add a commandline server test runner (#789)

This is similar to the cmdline tool, but acts a simple HTTP RPC test runner.

This is significantly faster than using the cmdline runner to run each test in isolation, as it remove the overhead of scanning for tests, and constructing a new device each test.

Co-authored-by: Austin Eng <7866475962f30d05c6be99ab4f8ad1431d92209f@chromium.org>
gpuweb/cts,gpuweb/cts,gpuweb/cts