Remove mirror::String::java_lang_String_.

And simplify ClassLinker::InitWithoutImage().
And finish ObjPtr<>-ification of annotation processing.

Test: m test-art-host-gtest
Test: testrunner.py --host
Bug: 31113334
Change-Id: I882a6c2f2b2a88d6ba34e4759bac4a6caa54cafa
diff --git a/openjdkjvmti/ti_class.cc b/openjdkjvmti/ti_class.cc
index 1697092..9bea18a 100644
--- a/openjdkjvmti/ti_class.cc
+++ b/openjdkjvmti/ti_class.cc
@@ -715,7 +715,7 @@
     if (!klass->IsProxyClass() && klass->GetDexCache() != nullptr) {
       art::StackHandleScope<1> hs(soa.Self());
       art::Handle<art::mirror::Class> h_klass = hs.NewHandle(klass);
-      art::mirror::ObjectArray<art::mirror::String>* str_array =
+      art::ObjPtr<art::mirror::ObjectArray<art::mirror::String>> str_array =
           art::annotations::GetSignatureAnnotationForClass(h_klass);
       if (str_array != nullptr) {
         std::ostringstream oss;