Remove WrapperWorldType from V8 binding

- Now that domTemplate() is always used for the current world, this CL removes a WrapperWorldType parameter from domTemplate(). Alternaltely, domTemplate() looks up the current world inside domTemplate().

- Now that DOMConfiguration methods are always used for the current world, this CL removes a WrapperWorldType parameter from the DOMConfiguration methods. Alternaltely, the methods look up the current world inside the methods.

- This CL removes WrapperWorldType, worldType() and worldTypeInMainThread() completely.

BUG=341032

Review URL: https://codereview.chromium.org/176963017

git-svn-id: svn://svn.chromium.org/blink/trunk@168978 bbb929c8-8fbe-4397-9dbb-9b2b20218538