RFR 8221698 Remove redundant includes from popular header files

[Ioi Lam]

https://bugs.openjdk.java.net/browse/JDK-8221698
http://cr.openjdk.java.net/~iklam/jdk13/8221698-remove-redundant-includes.v01/

The following files are included by some popular header files. This 
causes them to be included by almost all HotSpot C files. However, these 
header are for features that are not commonly used. Excluding them can 
improve HotSpot build speed by 1~2%.

   histogram.hpp
   classLoader.hpp
   utf8.hpp
   moduleEntry.hpp
   packageEntry.hpp

Thanks
- Ioi