Table rows are not totally invalidated after r170349

The change removed
RenderTableRow::clippedOverflowRectForPaintInvalidation
but the row's visual overflow doesn't include any cells
spanning several rows, which is required to be able to
invalidate rows correctly.

The fix is to include the spanning cells into the
row's visual overflow. Because they both share the
section's coordinate system, we need to translate the
cell's coordinate into the row's to avoid some wrong
visual overflow (aka over-invalidations).

BUG=417060

Review URL: https://codereview.chromium.org/673533002

git-svn-id: svn://svn.chromium.org/blink/trunk@184296 bbb929c8-8fbe-4397-9dbb-9b2b20218538