Reset mBufferInfos for setBufferInfo(s)

Since any of the setBufferInfo(s) can be converted
to BufferInfos in getBufferInfos, a reset is required
for mBufferInfos for every setBufferInfo(s)

Bug: 325512893
Test: atest android.mediav2.cts.CodecDecoderBlockModelMultiAccessUnitTest

Change-Id: Ibf28ad0983985bfb93f3bffe426677729430d06a