hg: jdk/sandbox: 8217994: os::print_hex_dump should be more resilient against unreadable memory

[chris.hegarty at oracle.com]

Changeset: 556122252316
Author:    shade
Date:      2019-01-30 19:45 +0100
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/556122252316

8217994: os::print_hex_dump should be more resilient against unreadable memory
Reviewed-by: zgu, stuefe, lucy

! src/hotspot/share/runtime/os.cpp
! test/hotspot/gtest/runtime/test_os.cpp