fstests: convert top level files and tools to SPDX

Scripted conversion, see script in initial SPDX license commit
message. Many files required touch-ups after the script had run
because of the old and widely different formats. most touchups were
to remove excess empty comment lines the script left behind.

Signed-off-by: Dave Chinner <dchinner@redhat.com>

tools/ag-wipe

@@ -1,23 +1,11 @@
 #!/usr/bin/perl -w
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2003-2004 Silicon Graphics, Inc.  All Rights Reserved.
+#
 use strict;
 use IO::File;
 use Getopt::Std;
 #
-# Copyright (c) 2003-2004 Silicon Graphics, Inc.  All Rights Reserved.
-#
-# This program is free software; you can redistribute it and/or
-# modify it under the terms of the GNU General Public License as
-# published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it would be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write the Free Software Foundation,
-# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
-#
 #
 # Modify a filesystem's superblock and AGF metadata structures
 # so that only a subset of the allocation groups will be used.