[CHROMIUM] Suppress more c4267 build warnings for Win64 targets
https://bugs.webkit.org/show_bug.cgi?id=107993

Source/WebCore:

No new tests. No behavior change.

Reviewed by Abhishek Arya.

* WebCore.gyp/WebCore.gyp:

Source/WTF:

Reviewed by Abhishek Arya.

* WTF.gyp/WTF.gyp:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@140910 268f45cc-cd09-0410-ab3c-d52691b4dbfc