Request for review: 7117052 instanceKlass::_init_state can be u1 type

[Jiangli Zhou]

The instanceKlass::_init_state is defined as instanceKlass::ClassState 
type, which is an enum. Currently there are 7 class states defined. The 
instanceKlass::_init_state can be changed to u1 type, which could hold 
up 256 states. There are unused bytes after 
instanceKlass::_idnum_allocated_count field. Changing _init_state to u1 
and move it to after the _idnum_allocate_count field would save 4-byte 
for each loaded class.

http://cr.openjdk.java.net/~jiangli/7117052/webrev.00/

Thanks,

Jiangli