Add hashtable test

compiler/testData/codegen/box/collections/inheritFromHashtable.kt

@@ -0,0 +1,11 @@
+// TARGET_BACKEND: JVM
+// WITH_RUNTIME
+// FULL_JDK
+import java.util.Hashtable
+
+class A : Hashtable<String, String>()
+
+fun box(): String {
+    val sz = A().size
+    return "OK"
+}