Use new call to get ComponentContext

Fuchsia OS is making a change in the serving sequence for component
startup, to avoid a race condition in which clients attempt to connect
to services that are not yet exposed but will be.

This change is needed for a smooth transition to that new API.  The
Fuchsia SDK change has already rolled to Dart.

See: https://bugs.fuchsia.dev/p/fuchsia/issues/detail?id=50758
Change-Id: Ib1249dcf771e99f542343328918ae55497ddaf71
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/145700
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Filip Filmar <fmil@google.com>

runtime/platform/utils_fuchsia.cc

@@ -39,7 +39,7 @@ int Utils::VSNPrint(char* str, size_t size, const char* format, va_list args) {
 
 sys::ComponentContext* ComponentContext() {
   static std::unique_ptr<sys::ComponentContext> context =
-      sys::ComponentContext::Create();
+      sys::ComponentContext::CreateAndServeOutgoingDirectory();
   return context.get();
 }