Exclude glassfish Executor which does not permit wrapped runnables

[felixbarny]

fixes #589

[felixbarny]

Contains no tests because we would have to instrument java.util.concurrent.ThreadPoolExecutor which is loaded from the bootstrap class loader and thus can't be instrumented in unit tests.

[felixbarny]

Snapshot for this PR: elastic-apm-agent-1.6.1-SNAPSHOT.jar.zip

[felixbarny]

@mdindoffer could you give this snapshot a try?

elastic-apm-agent-1.6.1-SNAPSHOT.jar.zip

[mdindoffer]

@felixbarny Perfect, that seems to do the trick.

[codecov-io]

Codecov Report

Merging #596 into master will increase coverage by 0.02%.
The diff coverage is 66.66%.

@@             Coverage Diff              @@
##             master     #596      +/-   ##
============================================
+ Coverage      62.4%   62.42%   +0.02%     
  Complexity       68       68              
============================================
  Files           188      188              
  Lines          7062     7066       +4     
  Branches        814      814              
============================================
+ Hits           4407     4411       +4     
  Misses         2387     2387              
  Partials        268      268

Impacted Files	Coverage Δ	Complexity Δ
.../apm/agent/concurrent/ExecutorInstrumentation.java	52.63% <66.66%> (+5.57%)	0 <0> (ø)	⬇️

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