Change test as mentioned on PR

Author: rsoeldner

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

@@ -31,9 +31,8 @@ class TabcompleteTests extends ReplTest {
 
   @Test def tabCompleteModule: Unit =
     fromInitialState{ implicit s =>
-      val comp = tabComplete("scala.Pred").suggestions
-    assertTrue(s""""Expected single element "Predef" got: ${comp}""",
-      comp == List("Predef"))
+      val comp = tabComplete("scala.Pred")
+      assertEquals(comp.suggestions, List("Predef"))
     }
 
   @Test def autoCompleteValAssign: Unit =