RFR: 8151526: Print -Xlog configuration in the hs_err_pid file

[Max Ockner]

Hello,
Please review another Unified Logging change. They are almost done, and 
we are serious this time.

bug: https://bugs.openjdk.java.net/browse/JDK-8151526
webrev: http://cr.openjdk.java.net/~mockner/8151526.01/

The logging configuration is now printed in each hs_err file. The output 
is the same as you would see from -Xlog:logging=trace and it is obtained 
from LogConfiguration::describe().

Below is a sample of the hs_err contents. The Logging info is printed 
after VM Arguments and Whitebox, and before Environment Variables.

VM Arguments:
java_command: Kaboom
java_class_path (initial): .
Launcher Type: SUN_STANDARD

Logging:
Available log levels: off, trace, debug, info, warning, error
Available log decorators: time (t), uptime (u), timemillis (tm), 
uptimemillis (um), timenanos (tn), uptimenanos (un), hostname (hn), pid 
(p), tid (ti), level (l), tags (tg)
Available log tags: alloc, age, barrier, biasedlocking, bot, census, 
classhisto, classresolve, classinit, classload, classloaderdata, 
classunload, classpath, compaction, cpu, cset, defaultmethods, ergo, 
exceptions, exit, freelist, gc, heap, humongous, ihop, itables, jni, 
liveness, logging, marking, metaspace, modules, monitorinflation, os, 
phases, plab, promotion, preorder, protectiondomain, ref, refine, 
region, remset, safepoint, safepointcleanup, scavenge, scrub, 
stacktrace, start, startuptime, state, stats, stringdedup, stringtable, 
survivor, sweep, task, thread, tlab, time, verboseverification, verify, 
vmoperation, vtables
Log output configuration:
#0: stdout all=off uptime,level,tags,
#1: stderr all=warning uptime,level,tags,

Environment Variables:
JAVA_HOME=/scratch/mockner/UL/8151526/build/linux-x86_64-normal-server-fastdebug/images/jdk
PATH=/home/mockner/tools/webrev:/bin:/usr/bin:/usr/local/bin:/usr/sbin:/home/mockner/bin:/home/mockner/linux/bin
SHELL=/bin/bash
OS=Linux