Uniquefy gdb.base/catch-syscall.exp test names.

Uniquefy gdb.base/catch-syscall.exp test names.

catch-syscall.exp has a series of duplicated output in gdb.sum.  This
patch makes sure all test names are unique, using with_test_prefix.

Tested on x86_64 Fedora 17.

gdb/testsuite/
2013-10-09  Pedro Alves  <palves@redhat.com>

	* gdb.base/catch-syscall.exp (test_catch_syscall_without_args)
	(test_catch_syscall_with_args, test_catch_syscall_with_many_args)
	(test_catch_syscall_with_wrong_args)
	(test_catch_syscall_restarting_inferior)
	(test_catch_syscall_fail_nodatadir)
	(test_catch_syscall_without_args_noxml)
	(test_catch_syscall_with_args_noxml)
	(test_catch_syscall_with_wrong_args_noxml): Use with_test_prefix.