When run with the --verbose flag, and a test fails because the context
comparison fails, then print the unified diff between the JSON
serialization of context that was captured and the context when it
was replayed.
Bug: angleproject:5715
Change-Id: I86210d96e5bbdf63f1ed663ddf8dfcb33764cbea
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2821535
Commit-Queue: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
