Tests that debugger StepOut will stop inside next timeout handler.

Set timer for test function.
Call stack:
    0) callback1 (debugger-step-out-across-timeouts.js:21)
    [setTimeout]
    0) testFunction (debugger-step-out-across-timeouts.js:15)
    [setTimeout]
    0) scheduleTestFunction <omitted>
    <... skipped remaining frames ...>

Executing StepOut...
Call stack:
    0) callback2 (debugger-step-out-across-timeouts.js:27)
    [setTimeout]
    0) callback1 (debugger-step-out-across-timeouts.js:20)
    [setTimeout]
    0) testFunction (debugger-step-out-across-timeouts.js:15)
    [setTimeout]
    0) scheduleTestFunction <omitted>
    <... skipped remaining frames ...>