DevTools: remove unused preventFollow

The preventFollow was first introduced to prevent links in Elements panel's tree
outline and SSP from opening on click
https://codereview.chromium.org/661103002

A later migration to preventClick removed all instances of preventFollow except
the one in this CL:
https://codereview.chromium.org/2519213002

BUG=none

Review-Url: https://codereview.chromium.org/2904823003
Cr-Commit-Position: refs/heads/master@{#474884}

third_party/WebKit/Source/devtools/front_end/components/Linkifier.js

@@ -477,7 +477,7 @@ Components.Linkifier = class {
   static _handleClick(event) {
     var link = /** @type {!Element} */ (event.currentTarget);
     event.consume(true);
-    if (link.preventFollow || UI.isBeingEdited(/** @type {!Node} */ (event.target)))
+    if (UI.isBeingEdited(/** @type {!Node} */ (event.target)))
       return;
     var actions = Components.Linkifier._linkActions(link);
     if (actions.length)