Add a mid-sized integration test for the Dart Embedding Api which

runtime/lib/isolate.cc

Index: runtime/lib/isolate.cc
===================================================================
--- runtime/lib/isolate.cc	(revision 1762)
+++ runtime/lib/isolate.cc	(working copy)
@@ -87,7 +87,7 @@
 RawInstance* ReceivePortCreate(intptr_t port_id) {
   const String& class_name =
       String::Handle(String::NewSymbol("ReceivePortImpl"));
-  const String& function_name = String::Handle(String::NewSymbol("create_"));
+  const String& function_name = String::Handle(String::NewSymbol("_create"));
   const int kNumArguments = 1;
   const Array& kNoArgumentNames = Array::Handle();
   const Function& function = Function::Handle(
@@ -112,7 +112,7 @@
 
 static RawInstance* SendPortCreate(intptr_t port_id) {
   const String& class_name = String::Handle(String::NewSymbol("SendPortImpl"));
-  const String& function_name = String::Handle(String::NewSymbol("create_"));
+  const String& function_name = String::Handle(String::NewSymbol("_create"));
   const int kNumArguments = 1;
   const Array& kNoArgumentNames = Array::Handle();
   const Function& function = Function::Handle(
@@ -276,7 +276,7 @@
     // Check arguments to see if the specified library and classes are
     // loaded, this check will throw an exception if they are not loaded.
     if (init_successful && CheckArguments(library_url, class_name)) {
-      port_id = PortMap::CreatePort();
+      port_id = spawned_isolate->main_port();
       uword data = reinterpret_cast<uword>(
           new IsolateStartData(spawned_isolate,
                                strdup(library_url),