Benchmark the performance of whisper.cpp in the browser using WebAssembly

Link: https://whisper.ggerganov.com/bench/

Terminal version: examples/bench

# build using Emscripten (v3.1.2)
git clone https://github.com/ggerganov/whisper.cpp
cd whisper.cpp
mkdir build-em && cd build-em
emcmake cmake ..
make -j

The example can then be started by running a local HTTP server:

python3 examples/server.py

And then opening a browser to the following URL: http://localhost:8000/bench.wasm

To run the example in a different server, you need to copy the following files to the server's HTTP path:

# copy the produced page to your HTTP path
cp bin/bench.wasm/*       /path/to/html/
cp bin/libbench.worker.js /path/to/html/