In order to build the mesa llvmpipe driver for Android, llvm libraries
for Android are needed; force meson to use a fallback for llvm and
provide prebuilt libraries making them available to meson thanks to
a wrap file.
Enable other software drivers for the x86_64-linux-android build, but
also disable the amd and intel hardware drivers for now which don't
build correctly on Android.
Download the prebuilt LLVM libraries for Android in the container job
rather than in the build job, to avoid downloading some big artifacts
for every mesa version built for Android.
Reviewed-by: Eric Engestrom <None>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30895>
