Fixup for the cherrypick of 4b0d2c12 (r277458) into clang-800. The lit test used "nullptr", which clang-800 complains about, so let's just use NULL instead.
diff --git a/test/tsan/Darwin/realloc-zero.cc b/test/tsan/Darwin/realloc-zero.cc
index c5053c3..9826246 100644
--- a/test/tsan/Darwin/realloc-zero.cc
+++ b/test/tsan/Darwin/realloc-zero.cc
@@ -9,7 +9,7 @@
 #include <sys/mman.h>
 
 int main() {
-  void *p = realloc(nullptr, 0);
+  void *p = realloc(NULL, 0);
   if (!p) {
     abort();
   }