RFR: 8149991: Convert TraceSafepointCleanupTime to Unified Logging

[Rachel Protacio]

Hello!

Coming close to the end of the logging conversions for now! Here's one 
for TraceSafepointCleanupTime, which is turning into 
-Xlog:safepointcleanup=info. As it has been a product option, it is 
aliased in this change.

To reiterate the conclusion from the TraceStartupTime conversion, I ask 
that as long as there are no objections to the correctness of the code, 
we allow this implementation for now, and I will then file a follow-up 
bug for possible improvements to the switch statement and TraceTime 
function signature situation. Since this is the only other "TraceTime" 
conversion, TraceTime implementation changes will be more succinctly 
addressable after this SafepointCleanupTime change than before it.

Bug: https://bugs.openjdk.java.net/browse/JDK-8149991
Open webrev: http://cr.openjdk.java.net/~rprotacio/8149991.01/

Sample old output:

    $ java -XX:+TraceSafepointCleanupTime -version
    java version "9-internal"
    Java(TM) SE Runtime Environment (fastdebug build
    9-internal+0-2016-03-02-133604.rprotaci.8150083)
    Java HotSpot(TM) 64-Bit Server VM (fastdebug build
    9-internal+0-2016-03-02-133604.rprotaci.8150083, mixed mode)
    [deflating idle monitors, 0.0000088 secs]
    [updating inline caches, 0.0000007 secs]
    [compilation policy safepoint handler, 0.0000009 secs]
    [mark nmethods, 0.0000164 secs]
    [purging class loader data graph, 0.0000002 secs]

Sample new output:

    $ java -Xlog:safepointcleanup -version
    java version "9-internal"
    Java(TM) SE Runtime Environment (fastdebug build
    9-internal+0-2016-03-02-133610.rprotaci.8149991)
    Java HotSpot(TM) 64-Bit Server VM (fastdebug build
    9-internal+0-2016-03-02-133610.rprotaci.8149991, mixed mode)
    [0.348s][info][safepointcleanup] deflating idle monitors, 0.0000059 secs
    [0.348s][info][safepointcleanup] updating inline caches, 0.0000009 secs
    [0.348s][info][safepointcleanup] compilation policy safepoint
    handler, 0.0000006 secs
    [0.348s][info][safepointcleanup] mark nmethods, 0.0000191 secs
    [0.348s][info][safepointcleanup] purging class loader data graph,
    0.0000001 secs


Tested using JPRT and RBT hotspot and non-colo tests.

Thanks!
Rachel