Always check if instance method name collides with superclass static.

Always check if instance method name collides with superclass static.

Previously we only did this check if nothing was overridden.
Persumably that was intended as a speed optimization, since at first
glance it would seem that if the instance method overrides something,
then it can't possibly conflict with a static method in the
superclass.  However, that optimization doesn't work if the method
being overridden is in an interface (in that case the superclass can
still have a static method with the same name).  So just go ahead and
check in all cases.

BUG=dartbug.com/18947
R=scheglov@google.com

Committed: https://code.google.com/p/dart/source/detail?r=41501

[Paul Berry, 2014-11-04 19:02:57]

paulberry@google.com changed reviewers:
+ scheglov@google.com

[scheglov, 2014-11-04 19:10:13]

LGTM

[Paul Berry, 2014-11-04 19:31:41]

Committed patchset #1 (id:1) manually as 41501 (presubmit successful).