RFR: [backport] 8048241: Introduce umbrella header os.inline.hpp and clean up includes

[Lindenmaier, Goetz]

Hi,

I'd like to backport this change:
8048241: Introduce umbrella header os.inline.hpp and clean up includes

It did not apply cleanly, so I please need a review.
The context has changed in src/share/vm/runtime/arguments.cpp, the
change in the patch remained the same.

This is the webrev for the 8u repository:
http://cr.openjdk.java.net/~goetz/webrevs/8048241-osInc/webrev.8.00/

This is the change in 9:
http://hg.openjdk.java.net/jdk9/hs/hotspot/rev/08a2164660fb
and the webrev submitted to 9:
http://cr.openjdk.java.net/~goetz/webrevs/8048241-osInc/webrev.00/

Please review this.  I  please need a sponsor to push the change.

Best regards,
  Goetz.