Make sure that Dart_Ports are printed safely in the service protocol

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index b5bbdf602bc597f9ac2c12847bf59f2696da2b40..e0d594648f46345d7a554eabed9de4659535da17 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -1830,17 +1830,17 @@ static const char* ExceptionPauseInfoToServiceEnum(Dart_ExceptionPauseInfo pi) {
 void Isolate::PrintJSON(JSONStream* stream, bool ref) {
   JSONObject jsobj(stream);
   jsobj.AddProperty("type", (ref ? "@Isolate" : "Isolate"));
-  jsobj.AddFixedServiceId("isolates/%" Pd "",
-                          static_cast<intptr_t>(main_port()));
+  jsobj.AddFixedServiceId("isolates/%" Pd64 "",
+                          static_cast<int64_t>(main_port()));
 
   jsobj.AddProperty("name", debugger_name());
-  jsobj.AddPropertyF("number", "%" Pd "",
-                     static_cast<intptr_t>(main_port()));
+  jsobj.AddPropertyF("number", "%" Pd64 "",
+                     static_cast<int64_t>(main_port()));
   if (ref) {
     return;
   }
-  jsobj.AddPropertyF("_originNumber", "%" Pd "",
-                     static_cast<intptr_t>(origin_id()));
+  jsobj.AddPropertyF("_originNumber", "%" Pd64 "",
+                     static_cast<int64_t>(origin_id()));
   int64_t start_time_millis = start_time() / kMicrosecondsPerMillisecond;
   jsobj.AddPropertyTimeMillis("startTime", start_time_millis);
   {