RFR 8154447: Exempt classes under java.util.concurrent from MH.Lookup restrictions

[Paul Sandoz]

Hi,

Please review:

  http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8154447-mh-lookup-restricted-pkgs/webrev/ <http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8154447-mh-lookup-restricted-pkgs/webrev/>
  https://bugs.openjdk.java.net/browse/JDK-8154447 <https://bugs.openjdk.java.net/browse/JDK-8154447>

This is a quick fix to allow classes under java.util.concurrent to call MethodHandles.lookup(), and thus unblock the use of such classes using VarHandles.

To verify and ensure we don’t regress i included a simple test.

These fragile checks will be revisited later under another issue.

Paul.