Benchmark: Add JNI test for Decoder and Encoder

Test: adb shell am instrument -w -r  -e debug false -e class \
      'com.android.media.benchmark.tests.EncoderTest#testNativeEncoder' \
      com.android.media.benchmark/androidx.test.runner.AndroidJUnitRunner

Test: adb shell am instrument -w -r  -e debug false -e class\
      'com.android.media.benchmark.tests.DecoderTest#testNativeDecoder' \
      com.android.media.benchmark/androidx.test.runner.AndroidJUnitRunner

Bug: 140051680

Change-Id: I60582652e2e8b488ef87962add59ccd84fbb0094
19 files changed