test: split the single current test file into two - one having all th…

…e tests relevant only for the `iterified` function and the other all the tests relevant only for `iterifiedUnwrapped` (#48)

Split the single current test file into two - one having all the tests relevant only for the `iterified` function and the other all the tests relevant only for `iterifiedUnwrapped`, to give each direct coverage for all its behaviors including those overlapping with the other's.

In the former unified test suite, some tests where written based on `iterified` and others based on `iterifiedUnwrapped` based on concerns of convenience. Now, each of these has direct coverage for all of its behaviors individually, even for the features overlapping with the other's.