Rename and merge IDL extended attributes [CustomToV8] => [CustomWrap], [DoNotGenerateWrap] => [CustomToV8]

No changes to generated code.

This renames and merges some extended attributes:
[CustomToV8] (w/o [DoNotGenerateWrap]) => [CustomWrap]
[DoNotGenerateWrap, CustomToV8] => [CustomToV8]
This is more accurate naming;
next I'll merge these and others into [Custom].

[DoNotGenerateWrap] always includes [CustomToV8]
(and there's even a code check for this!)
...so I changed the logic to understand this.

Also a bit of Perl cleanup (some redundancies).

Review URL: https://codereview.chromium.org/80533002

git-svn-id: svn://svn.chromium.org/blink/trunk@162511 bbb929c8-8fbe-4397-9dbb-9b2b20218538