[11u] Backport 8241638: launcher time metrics always report 1 on Linux when _JAVA_LAUNCHER_DEBUG set

[linzang(臧琳)]

Hi All,
     May I have your help to review this tiny patch, it is a clean backport of 8241638.
     And this patch also include the backport of 8243539, which is the fix of the copyright update issue of 8241638.
     Webrev: http://cr.openjdk.java.net/~lzang/8241638/11u/webrev11/
     Issues: https://bugs.openjdk.java.net/browse/JDK-8241638
                  https://bugs.openjdk.java.net/browse/JDK-8243539

     Thanks!

BRs,
Lin