[Qt][WK2] REGRESSION(102228): lot of test failures after enabled page cache

[Qt][WK2] REGRESSION(102228): lot of test failures after enabled page cache
https://bugs.webkit.org/show_bug.cgi?id=73999

Reviewed by Kenneth Rohde Christiansen.

Those tests were failing because PageCache was enabled for WTR and they depend on
it being disable: they rely on onload being called after navigating back to a page.

WTR should run without PageCache enabled. This was fixed in r106005, so we can
unskip these now.

* platform/qt-wk2/Skipped:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@106023 268f45cc-cd09-0410-ab3c-d52691b4dbfc