Reduce header files including header files.

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

Change-Id: I8d13dce8512816db2820a27b24f5866cc871a04b
diff --git a/runtime/fault_handler.h b/runtime/fault_handler.h
index 97d3c2f..026f5b9 100644
--- a/runtime/fault_handler.h
+++ b/runtime/fault_handler.h
@@ -29,7 +29,7 @@
 
 namespace mirror {
 class ArtMethod;
-}       // namespace mirror
+}  // namespace mirror
 
 class FaultHandler;