Reduce header files including header files.

Main focus is getting heap.h out of runtime.h.

Change-Id: I8d13dce8512816db2820a27b24f5866cc871a04b
diff --git a/runtime/dex_instruction.cc b/runtime/dex_instruction.cc
index 0494f22..0a71d62 100644
--- a/runtime/dex_instruction.cc
+++ b/runtime/dex_instruction.cc
@@ -20,6 +20,7 @@
 
 #include <iomanip>
 
+#include "base/stringprintf.h"
 #include "dex_file-inl.h"
 #include "utils.h"