Reword a precondition message.

In "never be called after" the "be" is extraneous and should definitely be removed. I modified the entire phrase to what I think is more readable.

Author: omustardoG

core/java/androidx/test/core/app/InstrumentationActivityInvoker.java

@@ -289,7 +289,7 @@ public ActivityResult getActivityResult() {
       }
       checkNotNull(
           activityResult,
-          "onActivityResult never be called after %d milliseconds",
+          "onActivityResult was not called within %d milliseconds",
           ActivityLifecycleTimeout.getMillis());
       return activityResult;
     }