Remove old isolate API and update all code in the repository to use

tests/isolate/spawn_uri_vm_negative_test.dart

Index: tests/isolate/spawn_uri_vm_negative_test.dart
diff --git a/tests/isolate/v2_spawn_uri_vm_negative_test.dart b/tests/isolate/spawn_uri_vm_negative_test.dart
similarity index 87%
rename from tests/isolate/v2_spawn_uri_vm_negative_test.dart
rename to tests/isolate/spawn_uri_vm_negative_test.dart
index 1d621ba8ca97f1a8781e20cd2c5f6f1d193eeb4c..b56cc075a7ff6d1be049859103ff8a99a365a51c 100644
--- a/tests/isolate/v2_spawn_uri_vm_negative_test.dart
+++ b/tests/isolate/spawn_uri_vm_negative_test.dart
@@ -5,7 +5,7 @@
 // Negative test to make sure that we are reaching all assertions.
 // Note: the following comment is used by test.dart to additionally compile the
 // other isolate's code.
-// OtherScripts=v2_spawn_uri_child_isolate.dart
+// OtherScripts=spawn_uri_child_isolate.dart
 #library('spawn_tests');
 #import('../../lib/unittest/unittest.dart');
 #import('dart:isolate');
@@ -18,7 +18,7 @@ main() {
       expect(msg, equals('re: hello')); // should be hi, not hello
     }));
 
-    SendPort s = spawnUri('v2_spawn_uri_child_isolate.dart');
+    SendPort s = spawnUri('spawn_uri_child_isolate.dart');
     s.send('hi', port.toSendPort());
   });
 }