Since 1.4.0-dev-8774, we mangle functions returning inline class values,
including functions with return type 'kotlin.Result'. This causes
incompatibility when 1.4 compiler is used with 1.3 (or just some
pre-1.4.0-dev-8774) standard library.
Also, write "message from the future" on functions returning inline
class values indicating that they can be used since compiler version 1.4
(otherwise 1.3 compiler using 1.4 stdlib would fail to find some
@InlineOnly functions such as 'Result.success' and 'Result.failure').
Dmitry Petrov
94509bdb4e