const stabilizations: adjust run-pass tests.

src/test/run-pass/const-int-rotate.rs

@@ -1,5 +1,3 @@
-#![feature(const_int_rotate)]
-
 const LEFT: u32 = 0x10000b3u32.rotate_left(8);
 const RIGHT: u32 = 0xb301u32.rotate_right(8);
 

src/test/run-pass/const-int-sign.rs

@@ -1,5 +1,3 @@
-#![feature(const_int_sign)]
-
 const NEGATIVE_A: bool = (-10i32).is_negative();
 const NEGATIVE_B: bool = 10i32.is_negative();
 const POSITIVE_A: bool= (-10i32).is_positive();

src/test/run-pass/const-int-wrapping.rs

@@ -1,5 +1,3 @@
-#![feature(const_int_wrapping)]
-
 const ADD_A: u32 = 200u32.wrapping_add(55);
 const ADD_B: u32 = 200u32.wrapping_add(u32::max_value());