Proxy implementation

This rounds out the proxy implementation by adding missing pieces to the
class linker, extending tests and fixing issues in the runtime support.
There are also some tweaks for performance and to clean up Method/Object
a little.
A unit test of the functionality is "art/test/run-test 044"

Change-Id: Id94102d10b81cd9b12b95ba8618f6187490204c4
diff --git a/src/runtime_support.h b/src/runtime_support.h
index de41f47..ba0b0f1 100644
--- a/src/runtime_support.h
+++ b/src/runtime_support.h
@@ -32,6 +32,8 @@
 /* Helper for both JNI and regular compiled code */
 extern "C" void art_deliver_exception_from_code(void*);
 
+extern "C" void art_proxy_invoke_handler();
+
 #if defined(__arm__)
   /* Compiler helpers */
   extern "C" void* art_alloc_object_from_code(uint32_t type_idx, void* method);