Use refnanny for utility code

[0dminnimda]

The discussion that it's beneficial to have unility code to be tested for memory leaks yielded that responce

We have refnanny for references in generated code, but not utility code.

Note that you can use it also in utility code, if you put in the required declarations and use the refnanny incref/decref/gotref/giveref macros. We just don't normally do it because it's cumbersome to copy all the boiler plate code together and write refnanny code by hand. If it helps here, it might be worth using. (My guess is that there are quite a number of utility code functions that might benefit from this, especially in ObjectHandling.c and Builtins.c, which deal a lot with object references.

Originally posted by @scoder in #5219 (comment)

I think that it's gonna be nice to simplify initialisation and use of refnanny so it could be used i utility code as well