Added Java NMT, Debug & JMX Helpers

[pivotal-david-osullivan]

Summary

This PR adds support for Java Native Memory Tracking (NMT), JMX & Remote Debug features present in libjvm

A helper has been added for each feature:

NMT

Flags added:

"NMT_LEVEL_1=summary" - required to enable NMT successfully due to JDK bug
"-XX:+UnlockDiagnosticVMOptions"
"-XX:NativeMemoryTracking=summary" - (summary report of memory usage)
"-XX:+PrintNMTStatistics" - (prints memory usage data at VM exit)

Configuration:

• These features will be enabled by default but come with a small amount of overhead - to disable Java NMT, users can set BPL_JAVA_NMT_ENABLED=false at runtime.
• Users can also configure the NMT tracking level via the runtime variable BPL_JAVA_NMT_LEVEL which defaults to 'summary' and can be set to 'detail'

JMX

Flags added:

"-Djava.rmi.server.hostname=127.0.0.1"
"-Dcom.sun.management.jmxremote.authenticate=false"
"-Dcom.sun.management.jmxremote.ssl=false"

Configuration:

• BPL_JMX_ENABLED=<true/false> - false by default
• BPL_JMX_PORT=<port> - configure the port value

Debug

Flags added:

-agentlib:jdwp=transport=dt_socket,server=y,address=<*:port>,suspend=<true/false>

• BPL_DEBUG_ENABLED=<true/false> - false by default.
• BPL_DEBUG_PORT=<port> - 8000 by default.
• BPL_DEBUG_SUSPEND=<true/false> - suspend execution, false by default.

Use Cases

Checklist

• I have viewed, signed, and submitted the Contributor License Agreement.
• I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).

[dmikusa]

One other note. Shouldn't there be a go.mod & go.sum change to pull in the latest libjvm?