Using -Xlog:aot to diagnose AOT cache

[ioi.lam at oracle.com]

I have published a PR to allow -Xlog:aot to see all logging messages 
related to the AOT cache. Please see the PR for the design and examples.

      https://github.com/openjdk/jdk/pull/24895

Since the AOT cache has been developed on top of CDS, we have a lot of 
legacy logging code in HotSpot that uses the "cds" tag. We should 
eventually change all of those tags to "aot" [1]. However, there might 
be existing scripts that rely on -Xlog:cds, so we probably go through a 
deprecation process over several JDK releases (similar to what we do 
with HotSpot command-line options).

My proposal is

JDK 25: make -Xlog:aot as an "alias" to -Xlog:cds, so that people can 
start using the AOT cache with a consistent command-line interface.

JDK 26: print a warning when -Xlog:cds is specified

JDK 27: completely remove -Xlog:cds


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[1] https://bugs.openjdk.org/browse/JDK-8356317 - Replace all "cds" logs 
with "aot"