Adding GetHashCode override for .NET EventFiringWebElement

Author: jimevans

dotnet/src/support/Events/EventFiringWebDriver.cs

@@ -1582,6 +1582,15 @@ public override bool Equals(object obj)
 
                 return underlyingElement.Equals(other);
             }
+
+            /// <summary>
+            /// Return the hash code for this <see cref="EventFiringWebElement"/>.
+            /// </summary>
+            /// <returns>A 32-bit signed integer hash code.</returns>
+            public override int GetHashCode()
+            {
+                return this.underlyingElement.GetHashCode();
+            }
         }
     }
 }