8303054: Remove unused variables in GCTraceTimeLoggerImpl::log_end

Reviewed-by: tschatzl

Author: albertnetymk

src/hotspot/share/gc/shared/gcTraceTime.cpp

@@ -49,8 +49,6 @@ void GCTraceTimeLoggerImpl::log_start(Ticks start) {
 
 void GCTraceTimeLoggerImpl::log_end(Ticks end) {
   double duration_in_ms = TimeHelper::counter_to_millis(end.value() - _start.value());
-  double start_time_in_secs = TimeHelper::counter_to_seconds(_start.value());
-  double stop_time_in_secs = TimeHelper::counter_to_seconds(end.value());
 
   LogStream out(_out_end);