DOMException toString is not correct

DOMException toString is not correct

We used to print:

    "Error: HIERARCHY_REQUEST_ERR: DOM Exception 3"

Now we print a more useful message:

    "HierarchyRequestError: The operation would yield an incorrect node tree."

that is:

    `${error.name}: ${error.message}`

BUG=250895
R=abarth@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=152573

[arv (Not doing code reviews), 2013-06-17 18:16:09]

I apologize for the size of this patch. I don't know how to make it smaller.

[abarth-chromium, 2013-06-17 18:38:06]

lgtm

[arv (Not doing code reviews), 2013-06-17 18:48:39]

Committed patchset #2 manually as r152573 (presubmit successful).