remove redundant test

tests/compile-fail/reference_to_packed_unsafe.rs

@@ -1,16 +0,0 @@
-#![allow(dead_code, unused_variables)]
-
-#[repr(packed)]
-struct Foo {
-    x: i32,
-    y: i32,
-}
-
-fn main() {
-    let foo = Foo {
-        x: 42,
-        y: 99,
-    };
-    let p: *const i32 = &foo.x; //~ ERROR tried to access memory with alignment 1, but alignment 4 is required
-    let x = unsafe { *p + foo.x };
-}