CSS: Fall back to cache-less cascade when encountering explicitly inherited value.

CSS: Fall back to cache-less cascade when encountering explicitly inherited value.
<https://webkit.org/b/125968>

When encountering an explicitly inherited value for a property that's not
"statically inherited", drop out of the matched properties cache path
immediately instead of waiting for some coincidence to trigger it later on.

Fixes 3 asserting table tests:

- fast/table/border-collapsing/cached-69296.html
- tables/mozilla/bugs/bug27038-3.html
- tables/mozilla_expected_failures/marvin/backgr_border-table-row-group.html

Reviewed by Antti Koivisto.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@160820 268f45cc-cd09-0410-ab3c-d52691b4dbfc