Update vlc.js demo with wip upstream patchset

Test procedure:

bash compile.sh
# should download emsdk 2.0.17, download vlc and apply patches, build vlc extras/contribs and core with modules (using the same procedure as the previous compile.sh + generate_module_list.sh in extras/package/wasm-emscripten/build.sh) and compile and link a vlc.js demo.

# test with http://localhost:6931/vlc.html :
emrun --no_browser vlc.html