Rename runAsync to scheduleMicrotask.

tests/lib/async/zone_run_guarded_test.dart

Index: tests/lib/async/zone_run_guarded_test.dart
diff --git a/tests/lib/async/zone_run_guarded_test.dart b/tests/lib/async/zone_run_guarded_test.dart
index 5bb3e18c9394e3d7b151349db07c0f993a545174..60ffe5a3eccf11b6b1c648607855ea70407dfb81 100644
--- a/tests/lib/async/zone_run_guarded_test.dart
+++ b/tests/lib/async/zone_run_guarded_test.dart
@@ -57,7 +57,7 @@ main() {
   result = forked.runGuarded(() {
     Expect.identical(forked, Zone.current);
     events.add("run closure");
-    runAsync(() {
+    scheduleMicrotask(() {
       events.add("run closure 2");
       Expect.identical(forked, Zone.current);
       done.complete(true);
@@ -65,13 +65,13 @@ main() {
     });
     throw 1234;
   });
-  events.add("after nested runAsync");
+  events.add("after nested scheduleMicrotask");
   Expect.equals(499, result);
 
   done.future.whenComplete(() {
     Expect.listEquals(
         ["forked.run", "run closure", "forked.handleUncaught 1234",
-         "after nested runAsync", "forked.run", "run closure 2",
+         "after nested scheduleMicrotask", "forked.run", "run closure 2",
          "forked.handleUncaught 88" ],
         events);
     asyncEnd();