RFR: 8297912: HotSpot Style Guide should permit alignas (Second Proposal Attempt) [v2]

[Kim Barrett]

On Sun, 4 Dec 2022 18:18:00 GMT, Julian Waters <jwaters at openjdk.org> wrote:

>> [8252584](https://bugs.openjdk.org/browse/JDK-8252584) was integrated too early due to a mistake on my part, we should redo it and go through the proper approval process this time
>> 
>> (The changes in this commit are exactly identical to 8252584)
>
> Julian Waters 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 two additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into style
>  - HotSpot Style Guide

The MSVC implementation of `ATTRIBUTE_ALIGNED` using `__declspec(align(N))` has the same
limitation of needing the alignment value, and not being usable for types.

I happened to run into both the limitation to alignment values problem and
the lack of an XLC definition for ATTRIBUTE_ALIGNED today.

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

PR: https://git.openjdk.org/jdk/pull/11446