benchmark: Support "software" instance of codec2 service

If CreateFromService("default") fails, then get codec2client from
CreateFromService("software")

Bug: 147836127
Test: on Pixel 2, C2DecoderTest -P /data/local/tmp/MediaBenchmark/res/
Change-Id: Iedcaa3a462a5c27f5ef843ef1233c8d06ad3d1d1
1 file changed