Strope 'any' in Promise.idl

'any' is a reserved identifier, but is being used as a function name.
This is fixed by stroping by prefixing with a '_'.

(The Perl parser doesn't check this, because it doesn't lex first,
 but the Python parser dies, which is why I caught this.)

Spec is:
http://www.w3.org/TR/WebIDL/#idl-names
"""
A leading "_" is used to escape an identifier from looking like a reserved word so that, for example, an interface named “interface” can be defined. The leading "_" is dropped to unescape the identifier.
"""

This is the same issue as earlier CL; we've fixed the Perl lexer (Python was ok), so it automatically unstropes:
Issue 15842011: Rename "object" to "_object" in HTMLAppletElement.idl
https://codereview.chromium.org/15842011/

Review URL: https://chromiumcodereview.appspot.com/18355010

git-svn-id: svn://svn.chromium.org/blink/trunk@154101 bbb929c8-8fbe-4397-9dbb-9b2b20218538