RFR: 8339242: Fix overflow issues in AdlArena [v5]

[Kim Barrett]

On Fri, 6 Sep 2024 08:52:07 GMT, Casper Norrbin <duke at openjdk.org> wrote:

>> Hi everyone,
>> 
>> This PR addresses an issue in `adlArena` where some allocations lack checks for overflow. This could potentially result in successful allocations when called with unrealistic values.
>> 
>> The fix includes:
>> 
>> - Adding assertions to check for potential overflow.
>> - Reordering some operations to guard against overflow.
>
> Casper Norrbin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   assert + static pointer_delta fun

Looks good.

-------------

Marked as reviewed by kbarrett (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/20774#pullrequestreview-2286796683