hg: jdk/sandbox: stricly monotone nanos for chunkheader

[markus.gronlund at oracle.com]

Changeset: a79e68ec829a
Author:    mgronlun
Date:      2019-10-30 11:28 +0100
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/a79e68ec829a

stricly monotone nanos for chunkheader

! src/hotspot/share/jfr/recorder/repository/jfrChunk.cpp
! src/hotspot/share/jfr/recorder/service/jfrPostBox.hpp