C2 VTS: Enable AdaptiveBitrateTest only for CDD mandated encoders

CDD Mandates dynamic bitrate support for avc, hevc, vp8 and vp9
encoders only, hence AdaptiveBitrateTest is now enabled only
for these encoders.

Bug: 177497478
Test: atest VtsHalMediaC2V1_0TargetVideoEncTest
Change-Id: I3b3941b8bb98e15f3a90a27307c9ed20c382a621