update: remove redundant and misplaced merge tests

The "nothing to merge" case is covered by test-merge-default.t.

The "uncommitted changes" case is covered by test-merge1.t (and
others).

The "merge -f" case is covered by test-merge-force.t.

tests/test-up-local-change.t

@@ -83,10 +83,6 b''
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     1
   
-  $ hg --debug merge
-  abort: nothing to merge
-  (use 'hg update' instead)
-  [255]
   $ hg parents
   changeset:   0:c19d34741b0a
   user:        test
@@ -170,52 +166,6 b' create a second head'
   abort: uncommitted changes
   (commit and merge, or update --clean to discard changes)
   [255]
-  $ hg --debug merge
-  abort: uncommitted changes
-  (use 'hg status' to list changes)
-  [255]
-  $ hg --debug merge -f
-    searching for copies back to rev 1
-    unmatched files new in both:
-     b
-  resolving manifests
-   branchmerge: True, force: True, partial: False
-   ancestor: c19d34741b0a, local: 1e71731e6fbb+, remote: 83c51d0caff4
-   preserving a for resolve of a
-   preserving b for resolve of b
-   a: versions differ -> m
-  updating: a 1/2 files (50.00%)
-  picked tool 'true' for a (binary False symlink False)
-  merging a
-  my a@1e71731e6fbb+ other a@83c51d0caff4 ancestor a@c19d34741b0a
-   b: both created -> m
-  updating: b 2/2 files (100.00%)
-  picked tool 'true' for b (binary False symlink False)
-  merging b
-  my b@1e71731e6fbb+ other b@83c51d0caff4 ancestor b@000000000000
-  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
-  (branch merge, don't forget to commit)
-  $ hg parents
-  changeset:   1:1e71731e6fbb
-  user:        test
-  date:        Thu Jan 01 00:00:00 1970 +0000
-  summary:     2
-  
-  changeset:   2:83c51d0caff4
-  tag:         tip
-  parent:      0:c19d34741b0a
-  user:        test
-  date:        Thu Jan 01 00:00:00 1970 +0000
-  summary:     3
-  
-  $ hg diff --nodates
-  diff -r 1e71731e6fbb a
-  --- a/a
-  +++ b/a
-  @@ -1,1 +1,1 @@
-  -a2
-  +abc
-
 
 test a local add