Enable back media_list_player's tests.

This reverts "test: Disable test_media_list_player as it deadlocks."

This reverts commit 3403c427.

test/Makefile.am

@@ -11,15 +11,14 @@ check_PROGRAMS = \
 	test_libvlc_core \
 	test_libvlc_events \
 	test_libvlc_media_list \
+	test_libvlc_media_list_player \
 	test_libvlc_media_player \
 	test_src_misc_variables \
         $(NULL)
 
 # Disabled test:
 # meta: No suitable test file
-# media_list_player: deadlocks.
 EXTRA_PROGRAMS = \
-	test_libvlc_media_list_player \
 	test_libvlc_meta \
 	test_dummy \
 	$(NULL)