Bug 1269415 - Allow negative <pre width> values; r=jst

This aligns with the spec and all other UAs, although it's less logical.

dom/html/HTMLPreElement.cpp

@@ -37,7 +37,7 @@ HTMLPreElement::ParseAttribute(int32_t aNamespaceID,
 {
   if (aNamespaceID == kNameSpaceID_None) {
     if (aAttribute == nsGkAtoms::width) {
-      return aResult.ParseIntWithBounds(aValue, 0);
+      return aResult.ParseIntValue(aValue);
     }
   }