[Qt] Enable LINK_PREFETCH
https://bugs.webkit.org/show_bug.cgi?id=111158

Reviewed by Simon Hausmann.

Tools:

* qmake/mkspecs/features/features.pri:

LayoutTests:

Unskip tests depending on LINK_PREFETCH.

* platform/qt/TestExpectations:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144441 268f45cc-cd09-0410-ab3c-d52691b4dbfc