Don't give 'order' semantic errors special treatment

Just set the parse status to the (new) error code for "zero value" or
"negative value" and let it propagate.
This makes SVGDocumentExtensions::reportWarning dead, so remove it.

BUG=231612

Review URL: https://codereview.chromium.org/1645043002

Cr-Commit-Position: refs/heads/master@{#372176}
7 files changed