[11] Review request: 8195074: Improve signing mechanism on Mac 10.12+

[victor . drozdov]

Kevin,

Please review my changes for fixing the issue: " JDK-8195074: Improve 
signing mechanism on Mac 10.12+"

JIRA: https://bugs.openjdk.java.net/browse/JDK-8195074
Webrev: http://cr.openjdk.java.net/~vdrozdov/JDK-8195074/webrev.00/

--Victor