[8u60] Request for Approval: 8068573: POJO setter using [] syntax throws an exception

[Attila Szegedi]

Please approve.

Bug: https://bugs.openjdk.java.net/browse/JDK-8068573
jdk9 webrev: http://cr.openjdk.java.net/~attila/8068573/webrev.00
jdk9 review thread: http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-January/004095.html

Changes apply cleanly to jdk8u-dev after path reshuffling from modular source code layout. This changeset is actually incomplete, as I forgot to add a test file into it; this is fixed by the follow-up JDK-8068994 that is also requested for approval. The two will be pushed together. 

Thanks,
  Attila.