Enable layer related tests in virtual/regionbasedmulticol.

These tests are passing with recent changes, so they don't need to be
skipped anymore.

R=rune@opera.com
BUG=359877

Review URL: https://codereview.chromium.org/632643002

git-svn-id: svn://svn.chromium.org/blink/trunk@183297 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move painting code from SVGInlineTextBox to SVGInlineTextBoxPainter.

BUG=412088

Review URL: https://codereview.chromium.org/627773002

git-svn-id: svn://svn.chromium.org/blink/trunk@183298 bbb929c8-8fbe-4397-9dbb-9b2b20218538