Remove xfail-test from (now functional) test. Fixes #2323.

Author: nikomatsakis

src/test/run-pass/class-poly-methods-cross-crate.rs

@@ -1,4 +1,3 @@
-// xfail-fast
 // aux-build:cci_class_6.rs
 use cci_class_6;
 import cci_class_6::kitties::*;