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>