uncomment feature-gate testing for in PLACE BLOCK now that its in the parser.

Author: pnkfelix

src/test/compile-fail/feature-gate-placement-expr.rs

@@ -22,6 +22,6 @@ fn main() {
     let x = box (HEAP) 'c'; //~ ERROR placement-in expression syntax is experimental
     println!("x: {}", x);
 
-    // let x = in HEAP { 'c' }; // ERROR placement-in expression syntax is experimental
-    // println!("x: {}", x);
+    let x = in HEAP { 'c' }; //~ ERROR placement-in expression syntax is experimental
+    println!("x: {}", x);
 }