[tests] Only include stdint.h if we are in freestanding mode.

 - We shouldn't even try to include stdint.h in hosted mode, as the dependency
   on even parsing a platforms stdint.h might fail for some targets.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179723 91177308-0d34-0410-b5e6-96231b3b80d8

test/Headers/c11.c

@@ -21,12 +21,12 @@ _Static_assert(__alignof(c) == 4, "");
 
 #define __STDC_WANT_LIB_EXT1__ 1
 #include <stddef.h>
-#include <stdint.h>
 rsize_t x = 0;
 
 // If we are freestanding, then also check RSIZE_MAX (in a hosted implementation
 // we will use the host stdint.h, which may not yet have C11 support).
 #ifndef __STDC_HOSTED__
+#include <stdint.h>
 rsize_t x2 = RSIZE_MAX;
 #endif