Update nullptr.c

Removed duplicate test

Author: AidanGoldfarb

clang/test/Sema/nullptr.c

@@ -113,8 +113,5 @@ void foo(void *);
 void bar() { foo(__nullptr); }
 static_assert(nullptr == __nullptr);
 static_assert(_Generic(typeof(__nullptr), nullptr_t: true, default: false));
-
-void foo(struct S *);
-void bar() { foo(__nullptr); } // Test that it converts properly to an arbitrary pointer type without warning
 _Static_assert(__nullptr == 0); // Test that its value matches that of NULL
 _Static_assert(_Generic(__typeof(__nullptr), int : 0, void * : 0, default : 1)); // Test that it's type is not the same as what NULL would generally have.