Refactored BTraceEngine listeners to an appropriate class

[refactormachine]

BTraceEngine need to handle the listeners by himself, we have refactored the code to have the listeners be handled by another class.
We moved a few methods to a new separate class.

We created this refactoring using automatic tools. See our website
www.refactormachine.com

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This change is 

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@040424c). Click here to learn what that means.
The diff coverage is 0%.

@@            Coverage Diff            @@
##             master     #361   +/-   ##
=========================================
  Coverage          ?   29.65%           
  Complexity        ?     1184           
=========================================
  Files             ?      157           
  Lines             ?    15143           
  Branches          ?     2526           
=========================================
  Hits              ?     4491           
  Misses            ?    10047           
  Partials          ?      605

Impacted Files	Coverage Δ	Complexity Δ
...sses/com/sun/btrace/api/impl/BTraceEngineImpl.java	0% <0%> (ø)	0 <0> (?)
...com/sun/btrace/api/impl/BTraceEngineListeners.java	0% <0%> (ø)	0 <0> (?)

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[jbachorik]

Reviewed 2 of 2 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved