RFR (S) 8183203: Remove stubRoutines_os

[Mikael Gerdin]

Hi all,

Please review this change to remove stubRoutines_<os>.cpp.
They have been empty for ages, the Linux and Windows ones have never had 
a single source line besides #includes since their creation almost 16 
years ago and the Solaris one has been empty for almost 15 years.

Testing: JPRT build-only job
Bug: https://bugs.openjdk.java.net/browse/JDK-8183203
Webrev: http://cr.openjdk.java.net/~mgerdin/8183203/webrev/

/Mikael