Height of fixed height cell is not proper when cell's row is under row spanning cell.

If cell have fixed height then it's height should not changed till there is 
other rows present to take extra rowspan cell height.

Extra rowspan cell height, First, distributes to percent height spanning rows 
which is depend on table height. If extra rowspan cell height remains after 
distributing to percent height rows then remaining extra rowspan cell height 
distributes in auto spanning rows if auto spanning rows are present otherwise 
it distributes to remaining spanning rows.

R=jchaffraix@chromium.org
BUG=254914

Review URL: https://chromiumcodereview.appspot.com/18050007

git-svn-id: svn://svn.chromium.org/blink/trunk@154604 bbb929c8-8fbe-4397-9dbb-9b2b20218538