RFR: 8023524: Mechanism to dump generated lambda classes / log lambda code generation

[Henry Jen]

OK, hopefully we are close to the end here on comments, unless there are
security related issues. We still need +1 from a jdk8 "reviewer",

http://cr.openjdk.java.net/~henryjen/ccc/8023524/5/webrev

This update include what Peter's latest suggestion, and since we don't
have a reliable way to create read-only directory on Windows, we simply
skip the test on non-posix filesystems, that is, Windows.

Cheers,
Henry