Revert "Enable Scroll Animation for RenderLayerScrollableArea"

This reverts commit 6fd2fdfc9696ee205daf9a43d07c49d30c246aad.

Conflicts:
	LayoutTests/TestExpectations
	Source/core/page/PageAnimator.cpp
	Source/core/rendering/RenderLayerScrollableArea.cpp

BUG=383946

Review URL: https://codereview.chromium.org/343663003

git-svn-id: svn://svn.chromium.org/blink/trunk@176446 bbb929c8-8fbe-4397-9dbb-9b2b20218538