Assert that waitForStep steps go in increasing order. This should make race conditions like the one in https://crrev.com/c/4321809 much more obvious from the logs and catch some of the issues when writing or updates tests. The test that has to be updated here is an example why we probably don't want to just replace `== step` with `>= step` Bug: angleproject:8071 Change-Id: I2c740931046bb5a9115474b7d67f76e9a21c30a4 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4322049 Commit-Queue: Roman Lavrov <romanl@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>