Rename/remove exception description to message for consistency

Previously our DOM exceptions had both a message and desciption field.
They both return the same value and since DOM only has message I got
rid of description and renamed the usages to message.

BUG=None

Review URL: https://chromiumcodereview.appspot.com/17745002

git-svn-id: svn://svn.chromium.org/blink/trunk@153035 bbb929c8-8fbe-4397-9dbb-9b2b20218538
fast/multicol/newmulticol/columns-shorthand-parsing.html fails after r153028

TBR=
BUG=254219

Review URL: https://codereview.chromium.org/17738008

git-svn-id: svn://svn.chromium.org/blink/trunk@153036 bbb929c8-8fbe-4397-9dbb-9b2b20218538