RFR 8180437 Remaining renames of CAS misnomer "swap" => "set"

[Paul Sandoz]

Please review a minor cleanup of internal naming:

  http://cr.openjdk.java.net/~psandoz/jdk10/JDK-8180437-cas-swap-to-set/webrev/ <http://cr.openjdk.java.net/~psandoz/jdk10/JDK-8180437-cas-swap-to-set/webrev/>

Paul.