Merge "backport vp8/9 unsigned int overflow fix" am: c03eb8c06c am: 97913d2610 am: 07992cce10 am: e9f97ec3c3

Original change: https://android-review.googlesource.com/c/platform/external/libvpx/+/1700605

Change-Id: Ibae2280d97db536943e3935496aee7d96e72f1e2