IDL compiler: Remove |name| parameter in Python

Sync to r161053:
Remove |name| parameters from DOM attribute getters/setters
https://codereview.chromium.org/54523003/

BUG=239771
NOTRY=true
TBR=haraken

Review URL: https://codereview.chromium.org/45473004

git-svn-id: svn://svn.chromium.org/blink/trunk@161120 bbb929c8-8fbe-4397-9dbb-9b2b20218538