Update the WebIDL parser

Upstream doesn't allow downloading .tar.gz archives so update.sh was changed
to use unzip.

components/script/dom/bindings/codegen/parser/ext-attribute-no-value-error.patch

@@ -0,0 +1,11 @@
+--- WebIDL.py
++++ WebIDL.py
+@@ -3490,7 +3490,7 @@ class IDLBuiltinType(IDLType):
+                                       [self.location, attribute.location])
+                 assert not self.nullable()
+                 if not attribute.hasValue():
+-                    raise WebIDLError("[TreatNullAs] must take an identifier argument"
++                    raise WebIDLError("[TreatNullAs] must take an identifier argument",
+                                       [attribute.location])
+                 value = attribute.value()
+                 if value != 'EmptyString':