Make the nomathbuiltin.c test less demanding.

This should hopefully unbreak the Windows bots at http://bb.pgr.jp



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186906 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/nomathbuiltin.c

 // RUN: %clang_cc1 -fno-math-builtin -emit-llvm -o - %s | FileCheck %s
 
-// Check that the -fno-math-builtin option for -cc1 is working properly,
-// by disabling just math builtin generation (other lib functions will
-// be generated as builtins).
+// Check that the -fno-math-builtin option for -cc1 is working properly.
 
-extern char *p1, *p2;
 
 double pow(double, double);
-void *memcpy(void *, const void *, unsigned long);
 
 double foo(double a, double b) {
-  memcpy(p1, p2, (unsigned long) b);
-// CHECK: call void @llvm.memcpy
   return pow(a, b);
 // CHECK: call double @pow
 }