Request for review 8006537: Missing initialization of Metaspace variables with -Xshare:dump

[Jon Masamitsu]

  8006537: Missing initialization of Metaspace variables with -Xshare:dump

Always initialize _first_chunk_word_size and _first_class_chunk_word_size.
Prior to b73 these variables were not being used extensively (if at all)
when DumpSharedSpace was on.  With b73 they need to be used.

When DumpSharedSpace was on previous to b73 there was not a second
call to the constructor for VirtualSpaceNode so the initialization done for
DumpSharedSpace was not called a second time and did not cause a problem.
With b73 and DumpSharedSpace it is called a second time so the 
initialization
for DumpSharedSpace had to be short circuited. This is a workaround. A
better fix would be to move the DumpSharedSpace initialization code to an
appropriate place.

http://cr.openjdk.java.net/~jmasa/8006537/webrev.00/

Thanks.