Fixes #1313. Pre-nnbd tests for focus_A01_t01 and blur_A01_t01 updated to their version in master (#1345)

Co-authored-by: sgrekhov <[email protected]>

Author: sgrekhov

LibTest/html/Element/blur_A01_t01.dart

@@ -16,11 +16,7 @@ main() {
   var x = new ButtonElement();
   body.append(x);
 
-  asyncStart();
-  x.onBlur.listen((e) {
-    asyncEnd();
-  });
-
   x.focus();
   x.blur();
+  Expect.notEquals(x, document.activeElement);
 }

LibTest/html/Element/focus_A01_t01.dart

@@ -16,10 +16,6 @@ main() {
   var x = new ButtonElement();
   body.append(x);
 
-  asyncStart();
-  x.onFocus.listen((e) {
-    asyncEnd();
-  });
-
   x.focus();
+  Expect.equals(x, document.activeElement);
 }