RFR (Tedious) 8204301: Make OrderAccess functions available to hpp rather than inline.hpp files

[coleen.phillimore at oracle.com]

Summary: move orderAccess.inline.hpp into orderAccess.hpp and remove 
os.hpp inclusion and conditional os::is_MP() for fence on x86 platforms

See discussion in bug.  Left os::is_MP() conditional for arm32. Tested 
by Boris U, thanks!

open webrev at http://cr.openjdk.java.net/~coleenp/8204301.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8204301

Tested on mach5 hs-tier1-2 on Oracle platforms: linux-x64, windows-x64, 
macosx-x64 and solaris-sparcv9.  Built on linux-aarch64 and 
linux-zero.   Boris built on arm32.  There were no actual changes on 
s390 or ppc.

Thanks,
Coleen