Use RenderStyle::isCollapsibleWhiteSpace when renderer is available.

This patch replaces isCollapsibleWhitespace() with RenderStyle::isCollapsibleWhiteSpace
in places where renderer is available. The latter provides more accurate decision so we
should always use it when possible. Some test results require rebaseline but none of
them failed the test really and the new behavior is correct.

BUG=357226

Review URL: https://codereview.chromium.org/214523008

git-svn-id: svn://svn.chromium.org/blink/trunk@170706 bbb929c8-8fbe-4397-9dbb-9b2b20218538