unbreak profiler_unittest when linking statically

When linking statically we may end up calling ProfilerGetCurrentState
earlier than profiler is initialized. And we segfaulted on that early
call. Lets make us handle this case gracefully.

src/profiledata.cc

@@ -210,7 +210,7 @@ void ProfileData::GetCurrentState(State* state) const {
     state->start_time = start_time_;
     state->samples_gathered = count_;
     int buf_size = sizeof(state->profile_name);
-    strncpy(state->profile_name, fname_, buf_size);
+    strncpy(state->profile_name, fname_ ? fname_ : "", buf_size);
     state->profile_name[buf_size-1] = '\0';
   } else {
     state->enabled = false;