Bug 40666: Fix compiler depedencies for Firefox on Windows and updated Node.js

Removed mingw-w64 as a depdency from Firefox, since we take libssp directly from mingw-w64-clang (the default compiler for Windows now).

Also, take clang as a depdendency for Firefox only on Linux, since macOS and Windows contain it in their compiler packages.

Finally, updated Node.js to the version told us by the toolchain scripts.

Closes #40666 (closed) and #40667 (closed).