VEQ: Update tests to work on auto targets

The video encoding quality tests were using adb sync to push
input and json files to device. This approach doesn't work for
multi-user cases like automotive targets or headless mode.

Bug: 335104019
Test: adb shell cmd user set-system-user-mode-emulation headless
Test: atest CtsVideoQualityFloorHostTest
Change-Id: I1338b7df22a164bb3a975132df0a0849db5f6475