Bug#32007149 AUTOTEST FAILS TO PRODUCE BACKTRACE WITH LONG PATHS

Modifies atrt-backtrace.sh to use file(1) utility to fetch the path of
the binary from the core file instead of gdb since it fails to fetch the
complete path of the binary if the path exceeds 80 characters and
fetches only a part of it leading to the failure of generation of
symbolic backtrace.

Change-Id: Ib479f7dc10ec1aa72b2be447aea408e1019c45ea

Author: VarunNagaraju

Diff for: storage/ndb/test/run-test/atrt-backtrace.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-# Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2008, 2020, Oracle and/or its affiliates.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License, version 2.0,
@@ -64,10 +64,7 @@ fi
 #
 # get binary
 #
-tmp=`echo ${core}.tmp`
-gdb -c $core -x $bt -q 2>&1 | grep "Core was generated" | awk '{ print $5;}' | sed 's!`!!' | sed `echo "s/'\.//"` > $tmp
-exe=`cat $tmp`
-rm -f $tmp
+exe=`file $core | sed 's/.*execfn//' | cut -d"'" -f 2`
 
 if [ -x "$exe" ]
 then