RFR (L): JDK-6843347 Boundary values in some public GC options cause crashes

[Thomas Schatzl]

Hi all,

  after an internal review, please have a look at the current version.

The difference to the previous is
- change the type of MarkSweepAlwaysCompactCount from intx to uintx,
with related changes.

Difference to the first version
- minimum value for HeapSizePerGCThread is os::vm_page_size() (suggested
by Jon M.)

Bugs.sun
http://bugs.sun.com/view_bug.do?bug_id=6843347

JBS:
https://jbs.oracle.com/bugs/browse/JDK-6843347

Webrev:
http://cr.openjdk.java.net/~tschatzl/6843347/webrev.2/

Testing:
jprt

Thanks,
  Thomas