validate: plug some leaks

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3319>

subprojects/gst-devtools/validate/gst/validate/gst-validate-utils.c

@@ -769,6 +769,7 @@ _file_get_structures (GFile * file, gchar ** err,
               /* We let the last attempt fail and report an error in the
                * including code path */
             }
+            g_strfreev (include_dirs);
           }
 
           included_path = g_file_get_path (included);

subprojects/gst-devtools/validate/plugins/ssim/gstvalidatessim.c

@@ -180,6 +180,8 @@ runner_stopping (GstValidateRunner * runner, ValidateSsimOverride * self)
     else
       npassed++;
 
+    g_free (ref_path);
+
     min_avg = MIN (min_avg, mssim);
     min_min = MIN (lowest, min_min);
     total_avg += mssim;