RFR (XS): 8153734: TestHumongousReferenceObject.java occasionally crashes with "unable to allocate heap of 1g" on win32

[Thomas Schatzl]

Hi all,

  can I have reviews for this (simple) fix for the mentioned test
introduced in JDK-8151499?

It previously used 1g of java heap, but that this is sometimes too much
for win32. Instead of excluding win32 from the platforms to run this
test on, just decrease the heap size of its runs (and the number of
iterations it does).

CR:
https://bugs.openjdk.java.net/browse/JDK-8153734
Webrev:
http://cr.openjdk.java.net/~tschatzl/8153734/webrev/
Testing:
local testing

Thanks,
  Thomas