Make jni_internal_test a CommonRuntimeTest.

Also clean up proxy_test and reflection_test.

Test: m test-art-host-gtest
Change-Id: I7530855a40d7b9f7214ea7a069508ae1361b2b42
diff --git a/runtime/common_runtime_test.cc b/runtime/common_runtime_test.cc
index a20baa0..ca410d9 100644
--- a/runtime/common_runtime_test.cc
+++ b/runtime/common_runtime_test.cc
@@ -385,6 +385,13 @@
   }
 }
 
+void CommonRuntimeTestImpl::MakeInterpreted(ObjPtr<mirror::Class> klass) {
+  PointerSize pointer_size = class_linker_->GetImagePointerSize();
+  for (ArtMethod& method : klass->GetMethods(pointer_size)) {
+    class_linker_->SetEntryPointsToInterpreter(&method);
+  }
+}
+
 bool CommonRuntimeTestImpl::StartDex2OatCommandLine(/*out*/std::vector<std::string>* argv,
                                                     /*out*/std::string* error_msg) {
   DCHECK(argv != nullptr);