Fixed limitation for number of custom main() arguments on Android.

Limitation was size of the reference table because local refs were not deleted.

src/main/android/SDL_android_main.c

@@ -47,6 +47,7 @@ int Java_org_libsdl_app_SDLActivity_nativeInit(JNIEnv* env, jclass cls, jobject
                 arg = SDL_strdup(utf);
                 (*env)->ReleaseStringUTFChars(env, string, utf);
             }
+            (*env)->DeleteLocalRef(env, string);
         }
         if (!arg) {
             arg = SDL_strdup("");