use cc_benchmark for buffer_transport_benchmark

1/ GoogleBenchmark framework makes the benchmark much more streamlined
   and automated.
2/ Update on how we create binder server. Especially, to make the
   comparison fair between Binder and BufferHub, we limited the binder
   server to run in single threaded mode.
3/ Update the threading model on the producer side to fit with
   cc_benchmark's model.

Bug: 66921451
Bug: 63909629
Test: adb shell /data/buffer_transport_benchmark
      --benchmark_min_time=5
      --benchmark_format=json
Change-Id: I3b4c6d943bf4917f8f776efe1f8dbe2d45c8e521