Increase memory limits for IcedTea

[Florian Weimer]

* Andrew Haley:

> 3.  There may be other untoward consequences of removing these limits:

It tends to break with "vm.overcommit_memory = 2".  AFAICT, IcedTea uses
the wrong flags with mmap/mprotect, or there is a kernel bug.

Unfortunately, it's not documented which flags you need to pass to make
an allocation not count against the beancounter.  Currently,
MAP_NORESERVE does not work, but allocating with PROT_NONE and setting
the proper flags later does.

It would be great if you could resolve this with the kernel team.  (It's
not just Java which would benefit from clear documentation, many other
memory managers would.)