convert junit tests to spock specs

[apanicker-nflx]

Following tests are converted:

• Workflow with no tasks
• Task def template

[codecov]

Codecov Report

Merging #1786 into dev will increase coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                dev    #1786      +/-   ##
============================================
+ Coverage     64.76%   64.78%   +0.02%     
- Complexity     3794     3796       +2     
============================================
  Files           295      295              
  Lines         18085    18085              
  Branches       1627     1627              
============================================
+ Hits          11712    11716       +4     
+ Misses         5554     5551       -3     
+ Partials        819      818       -1     

Impacted Files	Coverage Δ	Complexity Δ
...netflix/conductor/contribs/queue/QueueManager.java	60.20% <0.00%> (+4.08%)	16.00% <0.00%> (+2.00%)

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[coveralls]

Pull Request Test Coverage Report for Build 4351

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 18 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.08%) to 69.24%

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Files with Coverage Reduction	New Missed Lines	%
cassandra-persistence/src/main/java/com/netflix/conductor/dao/cassandra/CassandraEventHandlerDAO.java	8	68.42%
cassandra-persistence/src/main/java/com/netflix/conductor/dao/cassandra/CassandraMetadataDAO.java	10	55.44%

Totals
Change from base Build 4347:	-0.08%
Covered Lines:	12522
Relevant Lines:	18085

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💛 - Coveralls