Replace NULL with nullptr

Also fixed some lines that were too long, and a few other minor
details.

Change-Id: I6efba5fb6e03eb5d0a300fddb2a75bf8e2f175cb
diff --git a/runtime/mirror/iftable-inl.h b/runtime/mirror/iftable-inl.h
index d1309d2..b465d07 100644
--- a/runtime/mirror/iftable-inl.h
+++ b/runtime/mirror/iftable-inl.h
@@ -23,7 +23,7 @@
 namespace mirror {
 
 inline void IfTable::SetInterface(int32_t i, Class* interface) {
-  DCHECK(interface != NULL);
+  DCHECK(interface != nullptr);
   DCHECK(interface->IsInterface());
   const size_t idx = i * kMax + kInterface;
   DCHECK_EQ(Get(idx), static_cast<Object*>(nullptr));