This implements reading of the 'seq_profile' value from the
'av1C' atom per the spec description here:
https://aomediacodec.github.io/av1-isobmff/#av1codecconfigurationbox
https://aomediacodec.github.io/av1-spec/av1-spec.pdf (Section 5.2)

This also re-enables previously disabled tests and adds the various
bits necessary for av1 fuzzer tests.

Bug: 757047, 784993, 784607
Test: Updated unittests and fuzzertests.
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I05d8d42c8c022b7dc508ab8d212ad846ae1de8b6
Reviewed-on: https://chromium-review.googlesource.com/1107260
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Chrome Cunningham (In Paris) <chcunningham@chromium.org>
Reviewed-by: Tom Finegan <tomfinegan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576335}