add test for function pointer offsets

tests/compile-fail/fn_ptr_offset.rs

@@ -0,0 +1,11 @@
+use std::mem;
+
+fn f() {}
+
+fn main() {
+    let x : fn() = f;
+    let y : *mut u8 = unsafe { mem::transmute(x) };
+    let y = y.wrapping_offset(1);
+    let x : fn() = unsafe { mem::transmute(y) };
+    x(); //~ ERROR: tried to use an integer pointer or a dangling pointer as a function pointer
+}

tests/run-pass/thread-local.rs

@@ -42,7 +42,7 @@ unsafe extern fn dtor(mut ptr: *mut u64) {
     }
 
     // Check if the records matches what we expect. If yes, clear the cannary.
-    // If the record is wrong, the cannary will ever get cleared, leading to a leak -> test fails.
+    // If the record is wrong, the cannary will never get cleared, leading to a leak -> test fails.
     // If the record is incomplete (i.e., more dtor calls happen), the check at the beginning of this function will fail -> test fails.
     // The correct sequence is: First key 0, then key 1, then key 0.
     if RECORD == 0_1_0 {