Tests asynchronous call stacks for fetch.
Set timer for test function.
Captured call stacks in no particular order:
Call stack:
0) chained1 (async-callstack-fetch.js:20)
[Promise.then]
0) doFetch (async-callstack-fetch.js:19)
[setTimeout]
0) testFunction (async-callstack-fetch.js:14)
[setTimeout]
0) scheduleTestFunction <omitted>
<... skipped remaining frames ...>
Call stack:
0) chained4 (async-callstack-fetch.js:24)
[Promise.then]
0) doFetch (async-callstack-fetch.js:23)
[setTimeout]
0) testFunction (async-callstack-fetch.js:14)
[setTimeout]
0) scheduleTestFunction <omitted>
<... skipped remaining frames ...>