RFR: 8323730: Tweak TestZAllocationStallEvent.java to allocate smaller objects

[Stefan Johansson]

On Mon, 15 Jan 2024 14:23:59 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> This is a minor tweak to TestZAllocationStallEvent.java in an attempt to lower the risk of hitting OOME while provoking allocation stalls.
> 
> Tested by running tier5, where the test has been found to very intermittently cause problems.

👍

-------------

Marked as reviewed by sjohanss (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17426#pullrequestreview-1823389592