moved download.tst back to tst/ from tst-spec/

[cdwensley]

This follows the changes by @fingolfin to init.g and read.g in PR #55.

[cdwensley]

@ThomasBreuer - can you review this please, as I cannot remember why we put download.tst into a separate test folder, so have put it back into tst/.
@angeldelriomateos - sorry, did not intend to ask for a review from you, and cannot find how to remove you from the list of reviewers.

[ThomasBreuer]

As far as I see, download.tst has been moved from tst to tst-spec in pull request #52.
Concerning the question why the file has been moved away from tst, my understanding is that one wanted to leave out this file from the TestDirectory call that runs over all testfiles in tst, in order to run download.tst only in GAP 4.12 but not in GAP 4.13.

The proposed changes are fine from my point of view. If GAP 4.13 will contain some code that makes download.tst obsolete then presumably other changes will be needed in the utils package, and then adjusting download.tst will be part of these changes.

(I do not have the permissions to assign myself as a reviewer, or to approve the pull request.)

[cdwensley]

@ThomasBreuer - thanks for your comments - I will merge this PR.
It's very odd that you do not have permissions. When I go to the 'Reviewers' marker on the right I get a list of 68 potential reviewers, but you are not included. If I type '@ThomasBreuer' in the box, nothing happens.
I've still got an awful lot to learn about GitHub!

[cdwensley]

This PR now part of the utils-0.78 release of 17/11/22.