test: add an extra base changeset in test-obsolete.t

A fix to issue4982 (not fixed in this patch) will reinforce the filtering
during discovery. This will makes two of our test repositories appear
unrelated (because all common content is properly hidden). To avoid this, we
introduce an extra base changeset that will not get obsoleted. This affects
various test output so we put this addition in its own changeset.

tests/test-obsolete.t

@@ -712,29 +712,36 b' This test issue 3805'
 
   $ hg init repo-issue3805
   $ cd repo-issue3805
+  $ echo "base" > base
+  $ hg ci -Am "base"
+  adding base
   $ echo "foo" > foo
   $ hg ci -Am "A"
   adding foo
   $ hg clone . ../other-issue3805
   updating to branch default
-  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo "bar" >> foo
   $ hg ci --amend
   $ cd ../other-issue3805
   $ hg log -G
-  @  0:193e9254ce7e (draft) [tip ] A
+  @  1:29f0c6921ddd (draft) [tip ] A
+  |
+  o  0:d20a80d4def3 (draft) [ ] base
   
   $ hg log -G -R ../repo-issue3805
-  @  2:3816541e5485 (draft) [tip ] A
+  @  3:323a9c3ddd91 (draft) [tip ] A
+  |
+  o  0:d20a80d4def3 (draft) [ ] base
   
   $ hg incoming
   comparing with $TESTTMP/tmpe/repo-issue3805 (glob)
   searching for changes
-  2:3816541e5485 (draft) [tip ] A
+  3:323a9c3ddd91 (draft) [tip ] A
   $ hg incoming --bundle ../issue3805.hg
   comparing with $TESTTMP/tmpe/repo-issue3805 (glob)
   searching for changes
-  2:3816541e5485 (draft) [tip ] A
+  3:323a9c3ddd91 (draft) [tip ] A
   $ hg outgoing
   comparing with $TESTTMP/tmpe/repo-issue3805 (glob)
   searching for changes
@@ -749,7 +756,7 b' This test issue 3805'
   $ hg incoming http://localhost:$HGPORT
   comparing with http://localhost:$HGPORT/
   searching for changes
-  1:3816541e5485 (draft) [tip ] A
+  2:323a9c3ddd91 (draft) [tip ] A
   $ hg outgoing http://localhost:$HGPORT
   comparing with http://localhost:$HGPORT/
   searching for changes
@@ -767,13 +774,13 b' This test issue 3814'
   $ cd ..
   $ hg init repo-issue3814
   $ cd repo-issue3805
-  $ hg push -r 3816541e5485 ../repo-issue3814
+  $ hg push -r 323a9c3ddd91 ../repo-issue3814
   pushing to ../repo-issue3814
   searching for changes
   adding changesets
   adding manifests
   adding file changes
-  added 1 changesets with 1 changes to 1 files
+  added 2 changesets with 2 changes to 2 files
   2 new obsolescence markers
   $ hg out ../repo-issue3814
   comparing with ../repo-issue3814
@@ -783,24 +790,26 b' This test issue 3814'
 
 Test that a local tag blocks a changeset from being hidden
 
-  $ hg tag -l visible -r 0 --hidden
+  $ hg tag -l visible -r 1 --hidden
   $ hg log -G
-  @  2:3816541e5485 (draft) [tip ] A
-  
-  x  0:193e9254ce7e (draft) [visible ] A
+  @  3:323a9c3ddd91 (draft) [tip ] A
+  |
+  | x  1:29f0c6921ddd (draft) [visible ] A
+  |/
+  o  0:d20a80d4def3 (draft) [ ] base
   
 Test that removing a local tag does not cause some commands to fail
 
   $ hg tag -l -r tip tiptag
   $ hg tags
-  tiptag                             2:3816541e5485
-  tip                                2:3816541e5485
-  visible                            0:193e9254ce7e
+  tiptag                             3:323a9c3ddd91
+  tip                                3:323a9c3ddd91
+  visible                            1:29f0c6921ddd
   $ hg --config extensions.strip= strip -r tip --no-backup
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg tags
-  visible                            0:193e9254ce7e
-  tip                                0:193e9254ce7e
+  visible                            1:29f0c6921ddd
+  tip                                1:29f0c6921ddd
 
 Test bundle overlay onto hidden revision