ART: Dump class initialization stats durig SIGQUIT

Add class initialization metrics to the dump code.

Test: mmma art
Test: manual
Change-Id: Ib086662f7506bf7de403130fb2b7d3591d95f882
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index b40d61f..0c8d539 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -9320,6 +9320,9 @@
     }
   }
   os << "Done dumping class loaders\n";
+  Runtime* runtime = Runtime::Current();
+  os << "Classes initialized: " << runtime->GetStat(KIND_GLOBAL_CLASS_INIT_COUNT) << " in "
+     << PrettyDuration(runtime->GetStat(KIND_GLOBAL_CLASS_INIT_TIME)) << "\n";
 }
 
 class CountClassesVisitor : public ClassLoaderVisitor {