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

[Doug Simon]

> 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

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3558/files
  - new: https://git.openjdk.java.net/jdk/pull/3558/files/124019d7..c6be1437

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3558&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3558&range=02-03

  Stats: 11 lines in 10 files changed: 2 ins; 0 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3558.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3558/head:pull/3558

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