[master] RFR: Don't warn when UCOH is on by default

[Roman Kennke]

On Wed, 24 Apr 2024 05:23:30 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> When running testing with UCOH enabled by default in the code and non-generational ZGC the JVM prints this warning, which causes multiple failures in the testing. I'd like to propose that we  (at least temporarily) only write this warning if the user explicitly asked for UCOH.

Oh I believe this can be removed altogether. The reason why ZGC had problems was bad interaction/races with displaced headers, but with OMWorld this should no longer be the case.

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Changes requested by rkennke (Lead).

PR Review: https://git.openjdk.org/lilliput/pull/165#pullrequestreview-2018895847