tests: add test showing --continue not preserving --date and --user flags
This patch adds test showing that we don't preserve the user passed --date and
--user values in `hg graft`. I was fixing that and realized this is untested.
Adding tests before so that behavior change or the fix is easy to realize.
Differential Revision: https://phab.mercurial-scm.org/D3658
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.