MaxMetaspaceSize does not have to be aligned to metaspace commit alignment

Currently MaxMetaspaceSize is aligned to commit alignment in Metaspace::ergo_initialize().

That is unnecessary. MaxMetaspaceSize is just a number to compare the metaspace commit charge against. The fact that we commit in discrete uniform steps (since JEP-387, the size of a commit granule) makes no difference to that comparison.

This alignment introduced subtle display errors where the default value of max_uintx was aligned down, and that not-quite-max_uintx was not recognized to mean "infinite" (see JDK-8262099).