hg: jdk/submit-hs: 8200697: Add utility for spin wait with fallback to yield/sleep

[kim.barrett at oracle.com]

Changeset: 713d9b03e990
Author:    kbarrett
Date:      2018-04-09 01:22 -0400
URL:       http://hg.openjdk.java.net/jdk/submit-hs/rev/713d9b03e990

8200697: Add utility for spin wait with fallback to yield/sleep
Summary: Added SpinYield utility class.
Reviewed-by: dcubed, coleenp, dholmes
Contributed-by: kim.barrett at oracle.com, robbin.ehn at oracle.com

+ src/hotspot/share/utilities/spinYield.cpp
+ src/hotspot/share/utilities/spinYield.hpp
+ test/hotspot/gtest/utilities/test_spinYield.cpp