Add REPL tests for Java defined types. Proving scala#12346 is gone

Author: BarkingBad

compiler/test/dotty/tools/repl/JavaDefinedTests.scala

@@ -0,0 +1,16 @@
+package dotty.tools.repl
+
+import org.junit.Assert._
+import org.junit.Test
+
+class JavaDefinedTests extends ReplTest {
+  @Test def typeOfJavaDefinedString = fromInitialState { implicit s =>
+    run("String")
+    assertTrue(storedOutput().contains("Java defined class String is not a value"))
+  }
+
+  @Test def typeOfJavaDefinedClass = fromInitialState { implicit s =>
+    run("Class")
+    assertTrue(storedOutput().contains("Java defined class Class is not a value"))
+  }
+}