fix flaky sequential/test-timers-set-interval-excludes-callback-duration

[Trott]

• Version: 10.0-pre
• Platform: ubuntu1604_sharedlibs_debug_x64
• Subsystem: test

https://ci.nodejs.org/job/node-test-commit-linux-containered/1416/nodes=ubuntu1604_sharedlibs_debug_x64/console

03:37:24 not ok 2014 sequential/test-timers-set-interval-excludes-callback-duration
03:37:24   ---
03:37:24   duration_ms: 1.220
03:37:24   severity: fail
03:37:24   stack: |-
03:37:24     assert.js:45
03:37:24       throw new errors.AssertionError(obj);
03:37:24       ^
03:37:24     
03:37:24     AssertionError [ERR_ASSERTION]: false == true
03:37:24         at Timeout.setInterval [as _onTimeout] (/home/iojs/build/workspace/node-test-commit-linux-containered/nodes/ubuntu1604_sharedlibs_debug_x64/test/sequential/test-timers-set-interval-excludes-callback-duration.js:14:5)
03:37:24         at ontimeout (timers.js:455:11)
03:37:24         at tryOnTimeout (timers.js:304:5)
03:37:24         at Timer.listOnTimeout (timers.js:267:5)
03:37:24   ...

/cc @apapirovski

[apapirovski]

Should be easy to resolve. I think I was just too optimistic last time with the comparison value.