Web Inspector: toggling style should not start property edit first.

Web Inspector: toggling style should not start property edit first.
https://bugs.webkit.org/show_bug.cgi?id=89834

Reviewed by Yury Semikhatsky.

Source/WebCore:

Otherwise property flickers upon toggling.

* inspector/front-end/StylesSidebarPane.js:
(WebInspector.StylePropertyTreeElement.prototype):

LayoutTests:

* http/tests/inspector/elements-test.js:
(initialize_ElementTest.InspectorTest.dumpSelectedElementStyles):
(initialize_ElementTest.InspectorTest.toggleStylePropertyEnabled):
* inspector/styles/styles-disable-inherited.html:
* inspector/styles/styles-disable-then-change.html:
* inspector/styles/styles-disable-then-delete.html:
* inspector/styles/styles-disable-then-enable.html:
* inspector/styles/undo-property-toggle.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@121156 268f45cc-cd09-0410-ab3c-d52691b4dbfc