[chromium] Remove an obsolete comment about features.gypi
https://bugs.webkit.org/show_bug.cgi?id=76643

There can be only one features.gypi.

Reviewed by James Robinson.

* JavaScriptCore.gyp/JavaScriptCore.gyp:


git-svn-id: svn://svn.chromium.org/blink/trunk@105459 bbb929c8-8fbe-4397-9dbb-9b2b20218538