[cleanup] Move the LineClampUpdater definitions out of the header

https://bugs.webkit.org/show_bug.cgi?id=326264
<rdar://problem/189127202>

Reviewed by Antti Koivisto.

No change in functionality.

* Source/WebCore/Sources.txt:
* Source/WebCore/rendering/LineClampUpdater.cpp: Added.
(WebCore::LineClampUpdater::LineClampUpdater):
(WebCore::LineClampUpdater::~LineClampUpdater):
(WebCore::LineClampUpdater::setMaximumLines):
(WebCore::LineClampUpdater::resetLineClamp):
(WebCore::LineClampUpdater::maximumLinesForAutoClampPoint const):
* Source/WebCore/rendering/LineClampUpdater.h:
* Source/WebCore/rendering/RenderBlockFlow.cpp:
(WebCore::RenderBlockFlow::layoutInFlowChildren):
(WebCore::maximumLinesForAutoClampPoint): Deleted.

Canonical link: https://commits.webkit.org/322778@main