Tests "step out" functionality in debugger.

Debugger was enabled.
Set timer for test function.
Script execution paused.
Call stack:
    0) d (debugger-step-out.html:9)
    1) testFunction (debugger-step-out.html:14)
Stepping out...
Script execution resumed.
Script execution paused.
Call stack:
    0) testFunction (debugger-step-out.html:15)
Script execution resumed.
Debugger was disabled.