Tests that capturing asynchronous call stacks in debugger works if started after some time since the page loads.

Set timer for test function.
Captured call stacks in no particular order:
Call stack:
    0) timeoutOffCapturing2 (async-callstack-middle-run.js:27)

Call stack:
    0) timeoutOnCapturing (async-callstack-middle-run.js:32)
    [setTimeout]
    0) timeoutOffCapturing (async-callstack-middle-run.js:22)