android: actually use ReLinker
When loading libraries the `SDL.mContext` is still `null`. This results in
relinker code path in `SDL.loadLibrary(...)` always throwing a null exception
and fallbacking to system loader.
Fix it by passing the context explicitly.
(cherry picked from commit 6a2dd96ac7ce5c0575e91290a983048c0e5e6d2c)