Replace 2 uses of updateLogicalHeight with computeLogicalHeight

Replace 2 uses of updateLogicalHeight with computeLogicalHeight
https://bugs.webkit.org/show_bug.cgi?id=97486

Reviewed by Ojan Vafai.

More work for bug 96804.  This is just a refactoring.

No new tests, behavior should be the same as before.

* rendering/RenderFlowThread.cpp:
(WebCore::RenderFlowThread::computeLogicalHeight):
* rendering/RenderFlowThread.h:
* rendering/RenderMultiColumnFlowThread.cpp:
(WebCore::RenderMultiColumnFlowThread::computeLogicalHeight):
(WebCore):
* rendering/RenderMultiColumnFlowThread.h:
(RenderMultiColumnFlowThread):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@129427 268f45cc-cd09-0410-ab3c-d52691b4dbfc