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.

android-project/app/src/main/java/org/libsdl/app/SDLActivity.java

@@ -281,7 +281,7 @@ public class SDLActivity extends Activity implements View.OnSystemUiVisibilityCh
     // Load the .so
     public void loadLibraries() {
        for (String lib : getLibraries()) {
-          SDL.loadLibrary(lib);
+          SDL.loadLibrary(lib, this);
        }
     }