Coming soon: jtreg 7.4

[Christian Stein]

JDK folk,

This is a general heads-up that jtreg 7.4 is ready for use and
that we should soon update JDK to use it. There are not many
changes to the jtreg tool itself; the most significant change
in jtreg 7.4 are bug fixes to detect more failures and also an
update to include JUnit 5.10.2

Find a listing of all noteworthy changes at [1].

The plan is to make jtreg 7.4 the default version for JDK 24-ea
starting June 2024.

Thanks to everyone who has helped thus far!

[1] https://github.com/openjdk/jtreg/blob/jtreg-7.4+1/CHANGELOG.md