RFR(XS): 8225347: [s390] Unexpected exit from stack overflow test

[Doerr, Martin]

Hi,

test/hotspot/jtreg/compiler/interpreter/cr7116216/StackOverflow.java
fails on s390 because the VM exits unexpectedly. Further investigation shows that it crashes with segmentation fault when trying to throw a StackOverflowException.

Problem was only observed in fastdbg build, so it seems to be sufficient to increase StackShadowPages for debug builds.

Adding one page is sufficient to fix the issue, but I'd like to add 2 ones to be on the safe side:
http://cr.openjdk.java.net/~mdoerr/8225347_s390_shadow_pages/webrev.00/

Please review.

Best regards,
Martin