Replace MinObjectAlignmentSize usages for non-Java heap objects

MinObjectAlignmentSize and its derived "constants", describe the alignment of Java objects on the heap. The value can be used to increase the alignment, to free up more least-significant-bits in object pointers, which allows for larger memory ranges for compressed oops.

One usage of LogMinObjAlignmentInBytes was introduced to Symbol::identity_hash() with JDK-8087143.

In a pull request for JDK-8266642, similar code is suggested for the ClassLoaderData.

I think we should stop using LogMinObjAlignmentInBytes for C++ objects.