Correcting argument name in exception in DefaultWait{T}.cs

Signed-off-by: Jim Evans <[email protected]>

Author: Johnsavadkuhi

dotnet/src/support/UI/DefaultWait{T}.cs

@@ -63,7 +63,7 @@ public DefaultWait(T input, IClock clock)
 
             if (clock == null)
             {
-                throw new ArgumentNullException("clock", "input cannot be null");
+                throw new ArgumentNullException("clock", "clock cannot be null");
             }
 
             this.input = input;