added real UID to ActorPathBenchmarks (#6276)

While working on #6195 I realized that none of those `ActorPath`s actually have a set UID, thus we're missing that entire facet from both the parsing and serialization benchmarks.

src/benchmark/Akka.Benchmarks/Actor/ActorPathBenchmarks.cs

@@ -5,6 +5,7 @@
 // </copyright>
 //-----------------------------------------------------------------------
 
+using System;
 using Akka.Actor;
 using Akka.Benchmarks.Configurations;
 using BenchmarkDotNet.Attributes;
@@ -20,18 +21,25 @@ public class ActorPathBenchmarks
         private Address _sysAdr = new Address("akka.tcp", "system", "127.0.0.1", 1337);
         private Address _otherAdr = new Address("akka.tcp", "system", "127.0.0.1", 1338);
 
+        private string _actorPathStr;
+
+        [Params(1, 100000, int.MaxValue)]
+        public int Uid { get; set; }
+
         [GlobalSetup]
         public void Setup()
         {
             x = new RootActorPath(_sysAdr, "user");
             y = new RootActorPath(_sysAdr, "system");
-            _childPath = x / "parent" / "child";
+            var parentPath = x / "parent";
+            _childPath = new ChildActorPath(parentPath, "child", Uid);
+            _actorPathStr = _childPath.ToSerializationFormat();
         }
 
         [Benchmark]
         public ActorPath ActorPath_Parse()
         {
-            return ActorPath.Parse("akka.tcp://system/user/parent/child");
+            return ActorPath.Parse(_actorPathStr);
         }
 
         [Benchmark]