runtime: Update Proxy to assume 1 less direct method

Part of a libcore-side cleanup to remove dead code.

Requires a corresponding libcore change to run.

Bug: 26846861
Change-Id: I44ee74d8a4cbd7889d655c15c76dad8121c3297e
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 5ef199c..35e1ee6 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -4025,9 +4025,10 @@
 
 void ClassLinker::CreateProxyConstructor(Handle<mirror::Class> klass, ArtMethod* out) {
   // Create constructor for Proxy that must initialize the method.
-  CHECK_EQ(GetClassRoot(kJavaLangReflectProxy)->NumDirectMethods(), 19u);
+  CHECK_EQ(GetClassRoot(kJavaLangReflectProxy)->NumDirectMethods(), 18u);
   ArtMethod* proxy_constructor = GetClassRoot(kJavaLangReflectProxy)->GetDirectMethodUnchecked(
       2, image_pointer_size_);
+  DCHECK_EQ(std::string(proxy_constructor->GetName()), "<init>");
   // Ensure constructor is in dex cache so that we can use the dex cache to look up the overridden
   // constructor method.
   GetClassRoot(kJavaLangReflectProxy)->GetDexCache()->SetResolvedMethod(