Remove added two-phase-borrows flag

It seems whatever was causing problems has been fixed.

src/test/compile-fail/nll/region-ends-after-if-condition.rs

@@ -12,7 +12,7 @@
 // in the type of `p` includes the points after `&v[0]` up to (but not
 // including) the call to `use_x`. The `else` branch is not included.
 
-// compile-flags:-Zborrowck=compare -Znll -Ztwo-phase-borrows
+// compile-flags:-Zborrowck=compare -Znll
 
 #![allow(warnings)]
 #![feature(rustc_attrs)]