RFR (XXS): 8022784 TaskQueue misses minimal documentation and references for analysis

[Thomas Schatzl]

Hi all,

  need two quick reviews for the following change; the discussions for
"JDK-8006971 More missing barriers in taskqueues for RMO architectures"
showed that there is need for some minimal overview and references for
the taskqueue implementation.

This CR adds general documentation, and more importantly, references to
papers about the implementation.

Webrev:
http://cr.openjdk.java.net/~tschatzl/8022784/webrev/

Bugs.sun.com:
http://http://bugs.sun.com/view_bug.do?bug_id=8022784

JIRA:
https://jbs.oracle.com/bugs/browse/JDK-8022784

Testing:
N/A

Hth,
Thomas