Un-xfail tests that work now

Author: catamorphism

src/test/bench/shootout-nbody.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// xfail-test
 // based on:
 // http://shootout.alioth.debian.org/u32/benchmark.php?test=nbody&lang=java
 

src/test/run-pass/stat.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// xfail-test
 extern mod std;
 use io::WriterUtil;
 use std::tempfile;