RFR: 8258669: fastdebug jvm crashes when do event based tracing for monitor inflation

[Yangfei (Felix)]

Hi,

    Bug: https://bugs.openjdk.java.net/browse/JDK-8258669
    Webrev: http://cr.openjdk.java.net/~fyang/8258669/webrev.00 

    By referencing jdk11u, I think the reason is that we are not setting the "cause" in post_monitor_inflate_event for jdk8u.
    Proposed patch adds back the missing code changes in: 8138562: Event based tracing should cover monitor inflation. Also enabled code in MonitorInflateCauseConstant::serialize.
    Since this only adds some extra "cause" information for the monitor inflation event, I think it should be low risk.
    Performed full jtreg test based on the latest jdk8u-dev.  OK?

Thanks,
Felix