Update bootjdk for Java 25+

[keithc-ca]

Java 25 will soon be required in the head stream; for example, see:

• 8365699: Remove jdk.internal.javac.PreviewFeature.Feature enum values for features finalized in Java 25 or earlier

[pshipton]

First we need to require jdk25 testing to run on machines with the 17.1 runtime. We can try that now, although we may be short of machines, there are only 4 atm (but 2 are much faster). Perhaps you can add the following to this change at the end of the AIX section.

 extra_test_labels: 25: 'sw.tool.c++runtime.17_1' next: 'sw.tool.c++runtime.17_1' 

[pshipton]

Actually that's not quite right.

When we download jdk25 it will only run on machines with the 17.1 runtime, which means we need to build on machines with the 17.1 runtime, which means the resulting jvms will only run on machines with the 17.1 runtime.

I think we should do the test requirement separately first and see if it's ok, in case we need to back out. We have more machines coming, but it could be a while.

[pshipton]

Created #22910 for testing.

[pshipton]

This needs to wait until we have more machines available for testing.
#22910 (comment)