large file tests

[Bud Davis]

Hi !

I would like to add a directory to the test suite called


testsuite/gfortran.large_files


it would have it's own .exp file, which would run the tests only
if the environment variable GFORTRAN_LARGE_FILES is set as 
suggested in:

http://gcc.gnu.org/ml/fortran/2004-11/msg00237.html


the tests in this directory would be making large temporary
files and such would be painful for those with normal amounts
of memory and disk.

are these names OK ?  i kind of want to make sure these type
of things will be acceptable before I create the patch. 


at this time one test is available, which was submitted by
Tom Browder:

http://gcc.gnu.org/ml/fortran/2004-11/msg00167.html


i justify the need for this by the large number of fortran
users who care about this feature (large files).


--bud