ART: Add GetClassModifiers

Add support for GetClassModifiers. Add a test.

Bug: 31684578
Test: m test-art-host-run-test-912-classes
Change-Id: Ia14276d3139503ce35f7684bd846b371e9eafa25
diff --git a/runtime/openjdkjvmti/ti_class.h b/runtime/openjdkjvmti/ti_class.h
index 838c94c..619f50e 100644
--- a/runtime/openjdkjvmti/ti_class.h
+++ b/runtime/openjdkjvmti/ti_class.h
@@ -49,6 +49,8 @@
                                     jint* method_count_ptr,
                                     jmethodID** methods_ptr);
 
+  static jvmtiError GetClassModifiers(jvmtiEnv* env, jclass klass, jint* modifiers_ptr);
+
   static jvmtiError GetClassSignature(jvmtiEnv* env,
                                       jclass klass,
                                       char** signature_ptr,