test: wait for debounce for slow browsers in Interval debounce test

test: wait for debounce for slow browsers in Interval debounce test

Timeout delays are most often not respected and the differences between several timeouts running in parrallel can be huge. To prevent race conditions on slower browsers, we run the debounce test several time to wait for the debounced event to be called, which may be finally called way after the expected time.