RFR: 8191858: Add missing includes in memoryManager.hpp

[Stefan Karlsson]

Hi all,

Please review this trivial patch to add some missing includes to 
memoryManager.hpp.

http://cr.openjdk.java.net/~stefank/8191858/webrev.01
https://bugs.openjdk.java.net/browse/JDK-8191858

This was found when I was restructuring other parts of the code base.

Thanks,
StefanK