Linux has an unresolved hang if you resize a pipe with bytes
in it.
Since there's no obvious way to detect this happening, added a
workaround to disable resizing the pipe buffer if you set an
environment variable.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes#13309