IDL compiler: [NamedConstructor] arguments

This finished [NamedConstructor], and with it the main work of the IDL
compiler rewrite!

This mostly reuses existing [Constructor] logic, so Python in short.


I noticed two inconsistencies or two in exception raising:
failedToConstruct vs. failedToExecute and the name.

I've fixed this in the other CL:
IDL compiler: fix inconsistent constructor exceptions
https://codereview.chromium.org/114673006/

The logic is a lot clearer in the Jinja templates than in the Perl code,
so in this CL I've matched the Perl;
followup is primarily slightly messy Perl, and test result changes;
only Python change is removing overrides so behavior
falls back to being consistent.

BUG=239771
R=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/116803006

git-svn-id: svn://svn.chromium.org/blink/trunk@164043 bbb929c8-8fbe-4397-9dbb-9b2b20218538