Tests "step out" functionality in debugger.

Set timer for test function.
Script execution paused.
Call stack:
    0) d (debugger-step-out.js:14)
    1) testFunction (debugger-step-out.js:19)
Stepping out...
Script execution resumed.
Script execution paused.
Call stack:
    0) testFunction (debugger-step-out.js:20)
Script execution resumed.