RFR: 8218625: Remove dead code in relocInfo

[Claes Redestad]

Hi,

code/relocInfo.hpp|.cpp has a chunk of dead and unused methods and
fields, and there are related things in relocInfo_ext.hpp that is unused
on all platforms except arm which on closer inspection turns out to be
effectively dead as well.

Bug:    https://bugs.openjdk.java.net/browse/JDK-8218625
Webrev: http://cr.openjdk.java.net/~redestad/8218625/open.00/

Testing: tier1+2, sanity builds of the arm port

Thanks!

/Claes