RFR: 8288904: Incorrect memory ordering in UL

[Erik Österlund]

On Tue, 21 Jun 2022 19:12:55 GMT, Johan Sjölén <duke at openjdk.org> wrote:

> Please review this fix for JDK-8288904, thank you.
> 
> Currently running tier1-3 tests.

Might want to add a comment explaining the reason for the fence to be there.

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Changes requested by eosterlund (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9225