[Qt] Enable kerning by default
https://bugs.webkit.org/show_bug.cgi?id=112704

Reviewed by Jocelyn Turcotte.

Source/WebKit/qt:

Enable default kerning when fast kerning is available.

To support layout tests that depend on kerning being off by default,
a method is added to DumpRenderTreeSupportQt to reset the default.

* WebCoreSupport/DumpRenderTreeSupportQt.cpp:
(DumpRenderTreeSupportQt::resetDefaultTypesettingFeatures):
* WebCoreSupport/DumpRenderTreeSupportQt.h:
* WebCoreSupport/InitWebCoreQt.cpp:
(WebKit::initializeWebKitQt):

Tools:

Disable kerning by default, since some reference test expectations
expect kerning to be default off.

* DumpRenderTree/qt/TestRunnerQt.cpp:
(TestRunnerQt::reset):
* WebKitTestRunner/InjectedBundle/qt/ActivateFontsQt.cpp:
(WTR::activateFonts):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146340 268f45cc-cd09-0410-ab3c-d52691b4dbfc