tests: Various minor leak fixes in the GLib tests

Signed-off-by: Philip Withnall <withnall@endlessm.com>

glib/tests/option-context.c

@@ -2550,6 +2550,7 @@ double_free (void)
 
   g_option_context_free (context);
   g_clear_error (&error);
+  g_strfreev (argv);
 
 }
 

glib/tests/sequence.c

@@ -1379,6 +1379,8 @@ test_empty (void)
     }
 
   g_assert_true (g_sequence_is_empty (seq));
+
+  g_sequence_free (seq);
 }
 
 int

glib/tests/spawn-singlethread.c

@@ -394,6 +394,8 @@ test_spawn_nonexistent (void)
   g_assert_cmpint (exit_status, ==, -1);
 
   g_ptr_array_free (argv, TRUE);
+
+  g_clear_error (&error);
 }
 
 int