Add compiler-rt side test for no_sanitize("cfi") attribute

[krasin]

Summary

Add a test case for attribute((no_sanitize("cfi"))) being effective.

test/cfi/simple-fail.cpp

 // RUN: %expect_crash %t16 2>&1 | FileCheck --check-prefix=CFI %s
 
 // RUN: %clangxx_cfi_diag -o %t17 %s
 // RUN: %t17 2>&1 | FileCheck --check-prefix=CFI-DIAG %s
 
 // RUN: %clangxx -o %t18 %s
 // RUN: %t18 2>&1 | FileCheck --check-prefix=NCFI %s
 
+// RUN: %clangxx_cfi -DCHECK_NO_SANITIZE_CFI -o %t19 %s
+// RUN: %t19 2>&1 | FileCheck --check-prefix=NCFI %s
+
 // Tests that the CFI mechanism crashes the program when making a virtual call
 // to an object of the wrong class but with a compatible vtable, by casting a
 // pointer to such an object and attempting to make a call through it.
 
 // REQUIRES: cxxabi
 
 #include <stdio.h>
 #include "utils.h"
 
 struct A {
   virtual void f();
 };
 
 void A::f() {}
 
 struct B {
   virtual void f();
 };
 
 void B::f() {}
 
+#if defined(CHECK_NO_SANITIZE_CFI)
+__attribute__((no_sanitize("cfi")))
+#endif
 int main() {
   create_derivers<B>();
 
   A *a = new A;
   break_optimization(a);
 
   // CFI: 1
   // NCFI: 1