Add SwitchTargetSdkVersionRule stub for TlsDeprecationTest.

Needs further work as it looks like this is missing the
actual @rule it needs to work.

libcore-stub/src/main/java/libcore/junit/util/SwitchTargetSdkVersionRule.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package libcore.junit.util;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+public class SwitchTargetSdkVersionRule {
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.METHOD)
+    public @interface TargetSdkVersion {
+        int value();
+    }
+
+}