use ERR_SUBST to get around fact that the diagnostic

you get on a system with 32-bit time_t is not the same as
the one you get for a system where it's 64 bits wide:
- date: time 72057594037927935 is out of range
+ date: invalid date `@72057594037927935'

tests/misc/date

@@ -199,7 +199,8 @@ my @Tests =
      # 0000003
      ['uninit-64', '-d @72057594037927935',
       {OUT=>''},
-      {ERR => "date: invalid date `\@72057594037927935'\n"},
+      {ERR_SUBST => 's/.*//'},
+      {ERR => "\n"},
       {EXIT => 1},
      ],
     );