TestQuerySection: Adapt to changes of #BZBYSUITE-21 and use Thread.yield in test case
Use the internal/external class loading definition in order to access the instrumented class.
Add Thread.yield to the test case implementation in order to reduce unnnecessary busy waiting on single core machines.
Add checks that before the start and after the end of the execution no section is active.
Add check that there can be no active section during execution (unmeasured code section).
Paragraphs 1, 2 and 3 have been implemented. The case described in paragraph 4 is already covered in the existing test setup.