testExecutionManagerPerformance threshold to 7500ms from 2500ms

- For BasicTaskExeuctionTest.testExecutionManagerPerformance
- Saw 5601ms on buildhive
extract perf tests from BasicTaskExecutionTest

- created BasicTaskExecutionPerformanceTest
- convert that to Java so no overhead/jitter caused by groovy code
Merge pull request #803 from aledsage/fix/BasicTaskExecutionTest-timesensitive

Fix/basic task execution test timesensitive