Fix vm tests: introduce a hybrid file system so that the vm tests can find the

utils/application_snapshot.gni

Index: utils/application_snapshot.gni
diff --git a/utils/application_snapshot.gni b/utils/application_snapshot.gni
index 03661fb49818efe7efc5850c4413abb2ca96a658..9b5278672c0a1cd7b45b253fa21e723bbc56b852 100644
--- a/utils/application_snapshot.gni
+++ b/utils/application_snapshot.gni
@@ -25,7 +25,7 @@ template("application_snapshot") {
   if (defined(invoker.deps)) {
     extra_deps += invoker.deps
   }
-  extra_inputs = []
+  extra_inputs = [main_dart]

[Siggi Cherem (dart-lang), 2017/05/25 18:47:55]

Not sure if this is the proper way to fix it, but I noticed that changing
kernel-service.dart was not enough to trigger a rebuild of the snapshot, this
fixes that.

   if (defined(invoker.inputs)) {
     extra_inputs += invoker.inputs
   }