external/libgav1: update to v0.16.3

single-threaded is ~1.05-1.15x faster and multi-threaded is ~1.11x-1.29x
faster than the previous snapshot on a crosshatch device.

Bug: 151190209
Bug: 159304497
Test: playback, cts on sargo-userdebug / sargo_hwasan-userdebug
Test: aosp_arm-eng aosp_arm64-eng aosp_x86-eng aosp_x86_64-eng aosp_crosshatch-userdebug build
Change-Id: If064744bf1e840957b352b22a9f628e5d97fe6b4
189 files changed