[8u60] Request for Approval: 8079362: Enforce best practices for Node token API usage

[Attila Szegedi]

Please approve.

Bug: https://bugs.openjdk.java.net/browse/JDK-8079362
jdk9 webrev: http://cr.openjdk.java.net/~attila/8079362/webrev.00
jdk9 review thread: http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-May/004487.html

jdk8 webrev: http://cr.openjdk.java.net/~attila/8079362/webrev.8u-dev

Changes apply *almost* cleanly to jdk8u-dev after path reshuffling from modular source code layout, except for these deviations:
1. the 8u-dev changeset doesn’t contain changes to Parser API files in src/jdk.scripting.nashorn/share/classes/jdk/nashorn/api/tree directory, as this API is 9-only.
2. the 8u-dev changeset doesn’t contain changes in the ordering of imports in Lower.java, as it is already correct in 8u-dev (it was incorrect in 9).

I didn’t ask the team to review these trivial deviations; if you think it’s required I’ll ask them to do it.

Thanks,
  Attila.