Throw when <canvas> is not usable as image

This algorithm is used by createPattern() for which Chrome, Edge (different exception), Firefox, and Safari all throw. It's also used by drawImage() for which Edge, Firefox, and Safari throw. Chrome is the odd one out there.

This changed in 76782de and nobody picked it up then. That change also forgot to change the domintro boxes which still suggest throwing (and how I noticed this problem).

Author: annevk

source

@@ -62263,7 +62263,8 @@ try {
    https://software.hixie.ch/utilities/js/live-dom-viewer/?saved=2567 -->
 
    <li><p>If <var>image</var> is an <code>HTMLCanvasElement</code> object with either a horizontal
-   dimension or a vertical dimension equal to zero, then return <i>bad</i>.</p></li>
+   dimension or a vertical dimension equal to zero, then throw an
+   <span>"<code>InvalidStateError</code>"</span> <code>DOMException</code>.</p></li>
 
    <li><p>If <var>image</var> is an <code>ImageBitmap</code> object with its
    <span>[[Detached]]</span> internal slot value set to true, then throw an