RFR: 8219816: Add IsArray/RemoveArray type traits utilities

[Kim Barrett]

> On Feb 27, 2019, at 3:53 AM, Per Liden <per.liden at oracle.com> wrote:
> 
> Add IsArray/RemoveArray to our collection of type traits metaprogramming utilities.
> 
> This patch only adds the IsArray/RemoveArray utilities and their respective tests. A later patch I have in my queue that will actually make use of these.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8219816
> Webrev: http://cr.openjdk.java.net/~pliden/8219816/webrev.0
> 
> /Per

For completeness, there should probably be IsArray test cases for
const/volatile with size.

Otherwise, looks good.  I don't need another webrev for those
additional test cases.