RFR: JDK-8312203: Improve specification of Array.newInstance

[Joe Darcy]

Change one overload of java.lang.reflect.Array.newInstance to have an `@implSpec` of calling the other method.

I choose not to use a snippet tag here is this code is semantically only one line and doesn't need to be cut-and-pasted.

As adding an `@implSpec` is technically a (small) specification change, please also review the CSR:

https://bugs.openjdk.org/browse/JDK-8312208

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Commit messages:
 - Update copyright year.
 - JDK-8312203: Improve specification of Array.newInstance

Changes: https://git.openjdk.org/jdk/pull/14917/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14917&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312203
  Stats: 6 lines in 1 file changed: 1 ins; 3 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14917.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14917/head:pull/14917

PR: https://git.openjdk.org/jdk/pull/14917