nvidia-x11: add a symlink for libGLESv2.so.2 (close #9024)
nvidia's EGL stack looks for libGLESv2.so.2 at runtime (confirmed by
watching strace), however builder.sh only provides a libGLESv2.so.1
symlink.
@vcunat ported to legacy_340; older ones don't produce GLES.
authored by Spencer Janssen and committed by Vladimír Čunát ebe67d3c ff219393