The shell parameter expansion using # and ## is not supported in
Solaris 10 Bourne shell (/bin/sh). Even though this is POSIX, it is not fully
portable, so we should avoid it.
test_compress.sh now takes one command line argument:
a filename to be tested. If it begins with "compress_generated_"
the file will be created with create_compress_files.
This will allow parallel execution of the slow tests.