Duplicate compile-fail tests for intptrcast

tests/compile-fail/intptrcast_cast_int_to_fn_ptr.rs

@@ -0,0 +1,10 @@
+// Validation makes this fail in the wrong place
+// compile-flags: -Zmiri-disable-validation -Zmiri-seed=0000000000000000
+
+fn main() {
+    let g = unsafe {
+        std::mem::transmute::<usize, fn(i32)>(42)
+    };
+
+    g(42) //~ ERROR dangling pointer was dereferenced
+}

tests/compile-fail/intptrcast_null_pointer_deref.rs

@@ -0,0 +1,6 @@
+// compile-flags: -Zmiri-seed=0000000000000000
+
+fn main() {
+    let x: i32 = unsafe { *std::ptr::null() }; //~ ERROR invalid use of NULL pointer
+    panic!("this should never print: {}", x);
+}

tests/compile-fail/intptrcast_wild_pointer_deref.rs

@@ -0,0 +1,7 @@
+// compile-flags: -Zmiri-seed=0000000000000000
+
+fn main() {
+    let p = 44 as *const i32;
+    let x = unsafe { *p }; //~ ERROR dangling pointer was dereferenced
+    panic!("this should never print: {}", x);
+}