This is a workaround for a limitation right now. The html-generator has
no way to dynamically add JS sources (and that can't be done without
using a preprocessor library) so we hardcode js-runtime in it.
In the future, I think the correct behavior would be to move tools/
inside js-runtime along with a wasm application building SDK and get rid
of any direct JS access we have today (which is just
src/platform/wasm.zig and src/platform/mach.js).
