detect list of UNIVERSAL methods rather than hard coding list

[haarg]

We don't need to keep our own list of methods in UNIVERSAL, we can just use the actual list of methods that exists. Some things, like the import method, could end up existing based on the perl version or based on a prerequite loading UNIVERSAL.pm. There isn't really any value in keeping a hard coded list.

[pghmcfc]

This looks to be breaking the test with perl older than 5.22. For example, I'm getting this with 5.20.3:

t/cmop/metaclass_incompatibility_dyn.t ........................... ok
t/cmop/metaclass_inheritance.t ................................... ok
t/cmop/metaclass_loads_classes.t ................................. ok
t/cmop/metaclass_reinitialize.t .................................. ok
t/cmop/method.t .................................................. ok
t/cmop/method_modifiers.t ........................................ ok
"no" not allowed in expression at t/cmop/methods.t line 202, at end of line
BEGIN not safe after errors--compilation aborted at t/cmop/methods.t line 202.
t/cmop/methods.t .................................................
Dubious, test returned 255 (wstat 65280, 0xff00)
No subtests run
t/cmop/modify_parent_method.t .................................... ok
t/cmop/new_and_clone_metaclasses.t ............................... ok
t/cmop/null_stash.t .............................................. ok
t/cmop/numeric_defaults.t ........................................ ok

[haarg]

Fixed in master. New release will come soon.