Remove tests for unused IDL compiler features

Remove tests for unused features:
* sequence<SerializedScriptValue>
* [Immutable] on non-SVG attributes
* readonly constructor attributes
* static constructor attributes

Now Python passes TestTypedefs.idl!

TBR=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/137583006

git-svn-id: svn://svn.chromium.org/blink/trunk@165026 bbb929c8-8fbe-4397-9dbb-9b2b20218538