Request for approval & review: 8169911: Enhanced tests for jarsigner -verbose -verify after JDK-8163304

[Rob McKenna]

Hi folks,

Looking for approval for this backport from 9. The change adds some
extra cases to our jarsigner timestamp checks.

Bug: https://bugs.openjdk.java.net/browse/JDK-8169911
Webrev: http://cr.openjdk.java.net/~robm/8169911/
9 Changeset: http://hg.openjdk.java.net/jdk9/dev/jdk/rev/d09aebe3b50d

The only difference between 8 & 9 compensates for the use of List.of in
9.

    -Rob