Trace Tests: Print serialization diff on failure. Instead of only printing this with the "verbose" flag, print the diff of the serialization as an "info" message. This will make the diff show up on the bots. Bug: angleproject:5715 Change-Id: Ic9684b43cdf2d6ae248b5beab4317b0e939567c1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2979854 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Cody Northrop <cnorthrop@google.com>