RFR: 6805: Event emission only on exceptions

[Joshua Matsuoka]

This PR implements [JMC-6805](https://bugs.openjdk.java.net/browse/JMC-6805) allowing the agent to optionally only emit
events when exceptions are thrown by the instrumented method. This is configurable via an added xml option that when
set to true will only emit the event in the catch of the injected try-catch block.

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Commit messages:
 - Remove unused label
 - Clean up implementation and extraneous printlns
 - Add Lisence headers, cleanup
 - WIP Implementation of JMC-6805 - 3
 - WIP Implementation of JMC-6805
 - Merge remote-tracking branch 'upstream/master'
 - WIP Implementation of JMC-6805

Changes: https://git.openjdk.java.net/jmc/pull/92/files
 Webrev: https://webrevs.openjdk.java.net/jmc/92/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JMC-6805
  Stats: 225 lines in 9 files changed: 218 ins; 2 del; 5 mod
  Patch: https://git.openjdk.java.net/jmc/pull/92.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/92/head:pull/92

PR: https://git.openjdk.java.net/jmc/pull/92