update fileio test

update fileio test

This updates the fileio test to be parallel-safe.

2013-11-04  Tom Tromey  <tromey@redhat.com>

	* gdb.base/fileio.c (test_open, test_write, test_read)
	(test_lseek, test_close, test_stat, test_fstat)
	(test_isatty, test_system, test_rename, test_unlink):
	Use OUTDIR define.
	* gdb.base/fileio.exp: Define OUTDIR during compilation.
	Use standard_output_file.