Fixed RT-94731

CannotLocatePackageInINC exception has type which
isa 'Moose::Meta::TypeConstraint', but it should
be isa => 'Str'.

Also, test case for this exception was calling
resolve_metaclass_alias method directly, using trait
for testing this exception is a better idea, because it
explains this exception better.
Merge pull request #63 from moose/topic/rt-94731

Fixes RT#94731: Confusing error message when trying to load a trait class that does not exist in @INC