Fix ObjectEqualityComparer used in aggregatorstore (#2177)

src/OpenTelemetry/Metrics/ObjectArrayEqualityComparer.cs

@@ -41,7 +41,7 @@ namespace OpenTelemetry.Metrics
 
             for (int i = 0; i < len1; i++)
             {
-                if (obj1[i] != obj2[i])
+                if (!obj1[i].Equals(obj2[i]))
                 {
                     return false;
                 }

test/Benchmarks/Metrics/MetricsBenchmarks.cs

@@ -110,6 +110,11 @@ namespace Benchmarks.Metrics
         }
 
         [Benchmark]
+        public void CounterWith1LabelLocal()
+        {
+            this.counter?.Add(100, new KeyValuePair<string, object>("key", "value"));
+        }
+
         public void CounterWith3LabelsHotPath()
         {
             this.counter?.Add(100, this.tag1, this.tag2, this.tag3);