tests: in test-fncache.t, be more tolerant to the "Killed" message format

For example, on my box I'm seeing:

$TESTTMP.sh: line 250:  $pid Killed                  hg ci -qAm z

tests/test-fncache.t

@@ -335,7 +335,7 Clean cached versions
 # So we use a `|| echo` trick
 # XXX-CHG fixing chg behavior would be nice here.
   $ hg ci -qAm z || echo "He's Dead, Jim." 2>/dev/null
-  Killed (?)
+  *Killed* (glob) (?)
   He's Dead, Jim.
   $ cat .hg/store/fncache | sort
   data/y.i