ART: Add GetMethodDeclaringClass

Support GetMethodDeclaringClass to retrieve the declaring class
of a JNI method.

Extend test 910. Also cover proxies.

Bug: 31684812
Test: m test-art-host-run-test-910-methods
Change-Id: I8508f96f88692e540ef53f693ff85590b7553f19
diff --git a/runtime/openjdkjvmti/OpenjdkJvmTi.cc b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
index 10e877a..f95ec59 100644
--- a/runtime/openjdkjvmti/OpenjdkJvmTi.cc
+++ b/runtime/openjdkjvmti/OpenjdkJvmTi.cc
@@ -648,7 +648,7 @@
   static jvmtiError GetMethodDeclaringClass(jvmtiEnv* env,
                                             jmethodID method,
                                             jclass* declaring_class_ptr) {
-    return ERR(NOT_IMPLEMENTED);
+    return MethodUtil::GetMethodDeclaringClass(env, method, declaring_class_ptr);
   }
 
   static jvmtiError GetMethodModifiers(jvmtiEnv* env,