Don't ship libgcc and libstdc++ anymore in Windows builds based on ESR 24

While investigating #10252 (closed) I found that Firefox code is now statically linked against libgcc and libstdc++ (see: https://bugzilla.mozilla.org/show_bug.cgi?id=831707 and https://bugzilla.mozilla.org/show_bug.cgi?id=876416). Thus, we can avoid shipping them with our builds. Tests with the bundle in #10252 (closed) showed that it is indeed working without them contrary to the latest browser based on ESR 17.