RFR (M) 8199282: Remove ValueObj class for allocation subclassing for gc code

[coleen.phillimore at oracle.com]

This is the last of the installments of removing ValueObj for allocation 
subclassing.  This removes the type from allocation.hpp. This also 
removes some #includes for allocation.hpp from gc files that no longer 
need it for VALUE_OBJ_CLASS_SPEC subclassing.  We could do an additional 
pass to remove more allocation.hpp and globalDefinitions.hpp from files 
or remove this #include on a case-by-case basis.   That is, be aware 
that it may no longer be needed in any header files you happen to be 
working on.  Thanks to Kim for pointing this out.

Tested with mach5 tier1 and 2 on linux-x64, solaris-sparcv9, macos-x64 
and windows-x64.

open webrev at http://cr.openjdk.java.net/~coleenp/8199282.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8199282

Thanks,
Coleen