tests/test-hgk.t

tests: disable `test-git-interop.t` with a requirements directive

Note that the failures in this test affect all platforms.

I don't like this, but the test has been broken for awhile because of dirstate
API changes, and nobody noticed because the required `pygit2` package isn't
installed on the CI systems.  I did install it on the mac CI system, which
triggers this failure.  Disabling it is no worse than not running it due to the
missing package, but at least this way the CI systems can get the package
installed, and the test can be enabled and fixed eventually, without needing to
alter the CI systems.

The feature here is kind of abused.  I thought about adding one specifically to
test for CI, but didn't feel like doing it at this point.  Maybe if we need to
disable things to get the Windows CI off the ground (but that likely requires
testing for CI + platform).

Minimal hgk check

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "hgk=" >> $HGRCPATH
  $ hg init repo
  $ cd repo
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ hg debug-cat-file commit 0
  tree a0c8bcbbb45c
  parent 000000000000
  author test 0 0
  revision 0
  branch default
  phase draft
  
  adda
  $ echo b > b
  $ hg ci -Am addb
  adding b
  $ hg log -T '{node}\n'
  102a90ea7b4a3361e4082ed620918c261189a36a
  07f4944404050f47db2e5c5071e0e84e7a27bba9

  $ hg debug-diff-tree 07f494440405 102a90ea7b4a
  :000000 100664 000000000000 1e88685f5dde N	b	b
  $ hg debug-diff-tree 07f494440405 102a90ea7b4a --patch
  diff --git a/b b/b
  new file mode 100644
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +b

Ensure that diff-tree output isn't affected by diffopts
  $ hg --config diff.noprefix=True debug-diff-tree 07f494440405 102a90ea7b4a
  :000000 100664 000000000000 1e88685f5dde N	b	b
  $ hg --config diff.noprefix=True debug-diff-tree --patch 07f494440405 102a90ea7b4a
  diff --git a/b b/b
  new file mode 100644
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +b

  $ cd ..