"tensorflow" sample introduction

This sample demonstrates how to build tensorflow into WebAssembly with emcc toolchain and run it with iwasm. Please first install emsdk:

git clone https://github.com/emscripten-core/emsdk.git
cd emsdk
./emsdk install latest
./emsdk activate latest

And set up ensdk environment:

source emsdk_env.sh

Then run ./build.sh to build tensorflow and run it with iwasm, which basically contains the following steps:

hack emcc to delete some objects in libc.a
build tf-lite with emcc compiler
build iwasm with pthread enable and include libiary under libc-emcc
run benchmark model with iwasm: --max-secs 300: means the max training time cost is 5 minutes, you can adjust by yourself