ART: Refactor bit_utils and stl_util

Move iterator code from bit_utils.h into bit_utils_iterator.h. Move
Identity into stl_util_identity.h. Remove now unnecessary includes,
and fix up transitive users.

Test: m
Change-Id: Id1ce9cda66827c5d00584f39ed310b6b37629906
diff --git a/runtime/class_table.cc b/runtime/class_table.cc
index b71610a..c45bbe5 100644
--- a/runtime/class_table.cc
+++ b/runtime/class_table.cc
@@ -16,6 +16,7 @@
 
 #include "class_table-inl.h"
 
+#include "base/stl_util.h"
 #include "mirror/class-inl.h"
 #include "oat_file.h"