t1450: don't create unused files

t1450: don't create unused files

Test 'fsck error and recovery on invalid object type' in file
t1450-fsck.sh redirects output of a failing "git fsck" invocation to
files "out" and "err" to assert presence of error messages in the output
of the command.  Commit 31deb28f5e (fsck: don't hard die on invalid
object types, 2021-10-01) changed the way assertions in this test are
performed.  The test doesn't compare the whole standard error with
prepared file "err.expect" and it doesn't assert that standard output is
empty.

Don't create unused files "err.expect" and "out" in test 'fsck error and
recovery on invalid object type'.

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>