servo: Merge #17757 - Stop aborting release builds if we've missed invalidations before calling Servo_ResolveStyle (from bholley:downgrade_assertion); r=bholley

A lot of people are hitting this in [1]. I think having style (just potentially out-of-date) is less likely to cause weird crashes than failing to style the element entirely, so it's not worth inflicting this level of crashiness on the dogfood population.

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1381475

Source-Repo: https://github.com/servo/servo
Source-Revision: 602ef8bce1e7f270f0cb7a40a3c77e619c3d3863

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : e49f9265c3120f47f2470fa7e2f20f7c164a2bbd

servo/ports/geckolib/glue.rs

@@ -2781,7 +2781,7 @@ pub extern "C" fn Servo_ResolveStyle(element: RawGeckoElementBorrowed,
 
     // TODO(emilio): Downgrade to debug assertions when close to release.
     assert!(data.has_styles(), "Resolving style on unstyled element");
-    assert!(element.has_current_styles(&*data),
+    debug_assert!(element.has_current_styles(&*data),
                   "Resolving style on element without current styles");
     data.styles.primary().clone().into_strong()
 }