Remove some SOA from JNI internal.

Remove or reduce scope of scoped object accesses in JNI internal. Turn a
PrettyMethod and string compare into a pointer comparison.

Change-Id: I6f8ac8f6a4741916769288c4d6d411c7e0f40ef4
diff --git a/src/runtime.cc b/src/runtime.cc
index 8d88270..4ecc73a 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -854,6 +854,10 @@
     }
     self->TransitionFromRunnableToSuspended(kNative);
   }
+
+  // Initialize well known classes that may invoke runtime native methods.
+  WellKnownClasses::LateInit(env);
+
   VLOG(startup) << "Runtime::InitNativeMethods exiting";
 }