CodeEntryAlignment is constrained to not be bigger than CodeCacheSegmentSize that is itself constrained to be in the range(1, 1024).

CodeEntryAlignment is later implicitly narrow converted to int which looks like a bug but is okay. The data type should really be a uint16_t, but we have no such support for VM flags. uint will do, and will simplify the code greatly.

Also add explicit range on the flag.