New Test for 'vertical-align has no effect on a grid item'

The spec says that 'vertical-align' has no effect on a grid item.
Currently there are no tests for this, so added a new test case
for verifying the same.

BUG=395788

Review URL: https://codereview.chromium.org/543493004

git-svn-id: svn://svn.chromium.org/blink/trunk@181912 bbb929c8-8fbe-4397-9dbb-9b2b20218538