Android library update for benchmarking support

Test:
```
cd extension/android/benchmark
mkdir app/libs
cp <executorch.aar> app/libs/executorch.aar
./gradlew :app:installDebug

adb shell am start -n org.pytorch.minibench/org.pytorch.minibench.BenchmarkActivity --es model_path /data/local/tmp/model.pte
adb shell run-as org.pytorch.minibench cat files/benchmark_results.txt
```