fix(core): don't update taskCounts of setInterval

[JiaLiPassion]

fix angular/angular#20970 (comment)

don't update taskCount or trigger hasTask for setInterval.
otherwise the zone will always be unstable.

update

now the CI failed because new version jasmine complains, I have pinned the version of jasmine in #994.

[mhevery]

I don't think this is right. Why should setInterval be exempt from tasks?

[JiaLiPassion]

@mhevery
I just re-think it, you are right, we should not exempt interval from tasks, the interval should behave like

• call updateTaskCount +1 and trigger onHasTask when scheduleTask.
• will ** not ** call updateTaskCount and trigger onHasTask after runTask.
• will call updateTaskCount -1 and trigger onHasTask when cancelTask.

so if some interval task is active, zone will not be stable, but it is the correct behavior.

[JiaLiPassion]

@mhevery
I just re-think it, you are right, we should not exempt interval from tasks, the interval should behave like

call updateTaskCount +1 and trigger onHasTask when scheduleTask.
will ** not ** call updateTaskCount and trigger onHasTask after runTask.
will call updateTaskCount -1 and trigger onHasTask when cancelTask.
so if some interval task is active, zone will not be stable, but it is the correct behavior.

I will close this PR, the current behavior is correct. thank you!