tests: abmon-align: avoid test failure

tests: abmon-align: avoid test failure

* tests/ls/abmon-align: Don't remove (1d;) the first line of output.
That was making the test consider only 11 of 12 month names.
Rewrite not to use \(.*\), as that provoked a malfunction in GNU sed
on powerpc Mac OS X (though we don't know yet whether this is due to a
sed bug, or to miscompilation).  Nelson Beebe reported the test failure.