Support linking onnxruntime statically for Android

[csukuangfj]

This PR supports linking onnxruntime statically for Android (arm64-v8a, x86_64, and armeabi-v7a).

You need to run

export BUILD_SHARED_LIBS=OFF

./build-android-arm64-v8a.sh
./build-android-armv7-eabi.sh
./build-android-x86-64.sh

In the end, you only get one lib libsherpa-onnx-jni.so and you don't need to copy libonnxruntime.a to your project.

Note that if you download and unzip the onnxruntime static lib and you will find its size is about 1GB.

fangjuns-MacBook-Pro:build-android-x86-64-static fangjun$ ls -lh 1.17.1-static/lib/
total 1992056
-rw-r--r--  1 fangjun  staff   973M Dec 13 15:48 libonnxruntime.a

fangjuns-MacBook-Pro:build-android-x86-64-static fangjun$ ls -lh install/lib/libsherpa-onnx-jni.so
-rwxr-xr-x  1 fangjun  staff    23M Dec 13 17:05 install/lib/libsherpa-onnx-jni.so

Comparison of using static and dynamic link of onnxruntime in the final APK

Link onnxruntime statically	Link onnxruntime dynamically
You only need libsherpa-onnx-jni.so	You need libsherpa-onnx-jni.so and libonnxruntime.so

You can find pre-built aar files in the release page, e.g.,
https://github.com/k2-fsa/sherpa-onnx/releases/tag/v1.10.35