RFR: 8290464: Optimize ResourceArea zapping on ResourceMark release [v2]

[Thomas Stuefe]

On Tue, 19 Jul 2022 14:56:57 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> We have `ResourceMark` scopes where we either do not resource-allocate at all (see the bug for the example), or we do not allocate a lot in the arena. Still, in debug builds, we are zapping the entirety of `ResourceArea` chunk in those cases. This wastes testing cycles unnecessarily. Doing this in a bit smarter way -- zapping only the parts that were actually allocated in the chunk -- makes testing significantly faster.
>> 
>> Additional testing:
>>  - [x] Linux x86_64 fastdebug, `FieldSetAccessibleTest` (~10% faster)
>>  - [x] Linux x86_64 release, `FieldSetAccessibleTest` (no regressions)
>>  - [x] Linux x86_64 fastdebug, `hotspot:tier1` (~5% faster)
>>  - [x] Linux x86_64 release, `hotspot:tier1` (no regressions)
>>  - [x] Linux x86_64 fastdebug, `tier1` (~2% faster)
>>  - [x] Linux x86_64 release, `tier1` (no regressions)
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review comments: simplify

Looks good!

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Marked as reviewed by stuefe (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9543