tests: make and use a new `svnurlof.py` helper for constructing svn urls
The previous trick of a Python oneliner and some subshells is too hard
to make portable, and this lets us consolidate some Windows-specific
logic down to a single place.
Differential Revision: https://phab.mercurial-scm.org/D5766
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install::
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing::
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.