Fixing compilation error in benchmark code (#3442)

After introducing breaking changes for the 7.x release we accidentally broke the compilation of the benchmarks branch

Author: tishun

src/test/jmh/io/lettuce/core/protocol/EmptyClientResources.java

@@ -104,11 +104,6 @@ public CommandLatencyRecorder commandLatencyRecorder() {
         return LATENCY_COLLECTOR;
     }
 
-    @Override
-    public DnsResolver dnsResolver() {
-        return null;
-    }
-
     @Override
     public SocketAddressResolver socketAddressResolver() {
         return null;