Fixes for "null instanceof" and class initialization

First issue was that the codegen seemed to expect r0 to contain 0 for
a false result in the null object case. This is a quick fix to make
that true. Given that the code is doing the work of a null check and
pulling out the object's class, the code should probably just pass the
class to the helper function, making this a case of IsAssignableFrom,
not instanceof.

Second issues were related to missing EnsureInitialized calls in two
different code paths, one coming from reflection, one coming from
managed code. New Class::AllocObject assert should help keep us out of
trouble in the future in this area, although perhaps Heap::AllocObject
should have a check as well.

Change-Id: Ib7975b6457481c1ac85135d38f42c6061e6443a0
diff --git a/src/thread.h b/src/thread.h
index 01cc1cc..123a376 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -210,7 +210,7 @@
   Object* (*pGetObjStatic)(uint32_t, const Method*);
   void (*pSetObjStatic)(uint32_t, const Method*, Object*);
   void (*pCanPutArrayElementFromCode)(void*, void*);
-  bool (*pInstanceofNonTrivialFromCode) (const Object*, const Class*);
+  uint32_t (*pInstanceofNonTrivialFromCode) (const Object*, const Class*);
   void (*pCheckCastFromCode) (void*, void*);
   Method* (*pFindInterfaceMethodInCache)(Class*, uint32_t, const Method*, struct DvmDex*);
   void (*pUnlockObjectFromCode)(void*, void*);