[inspector] fixed console.count with empty stack

src/inspector/v8-console.cc

Index: src/inspector/v8-console.cc
diff --git a/src/inspector/v8-console.cc b/src/inspector/v8-console.cc
index 96537951a46ed3e19bfdf7ee344f7bd3fa3056fd..eab4051c548ea86b487e9206d598bd685406c3ad 100644
--- a/src/inspector/v8-console.cc
+++ b/src/inspector/v8-console.cc
@@ -344,9 +344,10 @@ void V8Console::countCallback(const v8::FunctionCallbackInfo<v8::Value>& info) {
   if (title.isEmpty()) {
     std::unique_ptr<V8StackTraceImpl> stackTrace =
         V8StackTraceImpl::capture(nullptr, 0, 1);
-    if (stackTrace)
+    if (stackTrace && !stackTrace->isEmpty()) {
       identifier = toString16(stackTrace->topSourceURL()) + ":" +
                    String16::fromInteger(stackTrace->topLineNumber());
+    }
   } else {
     identifier = title + "@";
   }