av: Register extractors from system_ext partition

Test: Extractor registered from /system_ext/lib[64]/extractors/
      - adb shell dumpsys media.extractor

Bug: 144478932

Change-Id: I1ab60912b5c4580b1dfe5d433acf7eec0d61b0f9

media/libstagefright/MediaExtractorFactory.cpp

@@ -302,6 +302,12 @@ void MediaExtractorFactory::LoadExtractors() {
 #endif
             "/extractors", NULL, *newList);
 
+    RegisterExtractors("/system_ext/lib"
+#ifdef __LP64__
+            "64"
+#endif
+            "/extractors", NULL, *newList);
+
     newList->sort(compareFunc);
     gPlugins = newList;