Tutorial: Step 4 improvements

Small changes to the text and CMake code for the fourth step of the
tutorial:

* Remove parameter from endfunction call
* Standardize on "binary directory" for test location
* Add additional information about a Release build.

Issue: #22663

Help/guide/tutorial/Step5/CMakeLists.txt

@@ -54,7 +54,7 @@ function(do_test target arg result)
   set_tests_properties(Comp${arg}
     PROPERTIES PASS_REGULAR_EXPRESSION ${result}
     )
-endfunction(do_test)
+endfunction()
 
 # do a bunch of result based tests
 do_test(Tutorial 4 "4 is 2")