libcore: Remove ptr::mut_addr_of since &mut is coerced to *mut

src/test/compile-fail/mutable-huh-ptr-assign.rs

@@ -16,8 +16,8 @@ fn main() {
     }
 
     unsafe {
-        let a = 0;
-        let v = ptr::mut_addr_of(&a);
+        let mut a = 0;
+        let v = &mut a;
         f(v);
     }
 }

src/test/compile-fail/mutable-huh-variance-ptr.rs

@@ -13,8 +13,8 @@
 extern mod std;
 
 fn main() {
-    let a = ~[0];
-    let v: *mut ~[int] = ptr::mut_addr_of(&a);
+    let mut a = ~[0];
+    let v: *mut ~[int] = &mut a;
 
     fn f(&&v: *mut ~[const int]) {
         unsafe {

src/test/run-fail/too-much-recursion-unwinding.rs

@@ -39,6 +39,6 @@ fn r(recursed: *mut bool) -> r {
 
 fn main() {
     let mut recursed = false;
-    let _r = r(ptr::mut_addr_of(&recursed));
+    let _r = r(&mut recursed);
     recurse();
 }