RFR: 8265403: consolidate definition of CPU features [v4]

Mon Apr 19 20:05:05 UTC 2021

On Mon, 19 Apr 2021 19:56:45 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

>> While porting [JDK-8224974](https://bugs.openjdk.java.net/browse/JDK-8224974) to Graal, I noticed that new CPU features were defined for x86 and AArch64 without being exposed via JVMCI. To avoid this problem in future, this PR updates x86 and AArch64 to define CPU features with a single macro that is used to generate enum declarations as well as vmstructs entries.
>> 
>> In addition, the JVMCI API is updated to exposes the new CPU feature constants and now has a check that ensure these constants are in sync with the underlying macro definition.
>
> Doug Simon has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - updated date in copyright
>  - added blank lines after macros

You need review from Runtime group too.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3558