tests: make sure no ambiguities remains after the commit

This will help to stabilize part of the test that are not relevant for what is
actually tested.

Differential Revision: https://phab.mercurial-scm.org/D11778

tests/test-dirstate-race2.t

@@ -1,48 +1,54 b''
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
   > exp-rc-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
 #endif
 
 Checking the size/permissions/file-type of files stored in the
 dirstate after an update where the files are changed concurrently
 outside of hg's control.
 
   $ hg init repo
   $ cd repo
   $ echo a > a
   $ hg commit -qAm _
   $ echo aa > a
   $ hg commit -m _
+# this sleep is there to ensure current time has -at-least- one second away
+# from the current time. It ensure the mtime is not ambiguous. If the test
+# "sleep" longer this will be fine.
+# It is not used to synchronise parallele operation so it is "fine" to use it.
+  $ sleep 1
+  $ hg status
 
   $ hg debugdirstate --no-dates
   n 644          3 (set  |unset)               a (re)
 
   $ cat >> $TESTTMP/dirstaterace.py << EOF
   > from mercurial import (
   >     extensions,
   >     merge,
   > )
   > def extsetup(ui):
   >     extensions.wrapfunction(merge, 'applyupdates', wrap)
   > def wrap(orig, *args, **kwargs):
   >     res = orig(*args, **kwargs)
   >     with open("a", "w"):
   >         pass # just truncate the file
   >     return res
   > EOF
 
 Do an update where file 'a' is changed between hg writing it to disk
 and hg writing the dirstate. The dirstate is correct nonetheless, and
 so hg status correctly shows a as clean.
 
   $ hg up -r 0 --config extensions.race=$TESTTMP/dirstaterace.py
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg debugdirstate --no-dates
   n 644          2 (set  |unset)               a (re)
   $ echo a > a; hg status; hg diff