RFR(S): 7901696: jtreg must set LIBPATH on aix/os400

[Lindenmaier, Goetz]

Hi

Jtreg sets LD_LIBRARY_PATH on aix and os400, where it must use
LIBPATH.

Please review this change. I please need a sponsor (or can I push myself?)
http://cr.openjdk.java.net/~goetz/wr16/7901696-jtreg_LIBPATH/webrev.01/

Best regards,
  Goetz.