RFR: 8350753: Deprecate UseCompressedClassPointers [v2]

[ExE Boss]

On Sun, 6 Apr 2025 09:08:34 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Deprecates UseCompressedClassPointers. For the lengthy description of why and how we do this, please read the lengthy [CSR](https://bugs.openjdk.org/browse/JDK-8350754).
>> 
>> Testing:
>> 
>> I ran all jtreg tests manually on Linux-x64 that used the flag in some form (55 tests) to ensure they don't trip over the added deprecation output.
>> 
>> I also tested the JVM on arm32 to verify that UseCompressedClassPointers had never been available there, and that we don't start printing a confusing deprecation message now.
>
> Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into JDK-8350753-Deprecate-UseCompressedClassPointers
>  - not on 32-bit
>  - Deprecate UseCompressedClassPointers

test/hotspot/jtreg/runtime/CommandLine/VMDeprecatedOptions.java line 65:

> 63:             // deprecated alias flags (see also aliased_jvm_flags):
> 64:             {"CreateMinidumpOnCrash", "false"},
> 65:             {"UseCompressedClassPointers", "false"},

`UseCompressedClassPointers` is not an alias flag:
Suggestion:

            {"UseCompressedClassPointers", "false"},

            // deprecated alias flags (see also aliased_jvm_flags):
            {"CreateMinidumpOnCrash", "false"},

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PR Review Comment: https://git.openjdk.org/jdk/pull/24436#discussion_r2030140764