RFR(S): 8241638: launcher time metrics alway report 1 on Linux when _JAVA_LAUNCHER_DEBUG set

[臧琳]

Dear All,
May I ask your help to review this tiny fix?
    Bug: https://bugs.openjdk.java.net/browse/JDK-8241638
    Webrev: http://cr.openjdk.java.net/~lzang/8241638/webrev01/
Thanks!

BRs,
Lin