Internal: Don't let `took` be negative.

`took` is computed based on the system clock and can be negative if the clock
time was updated during the execution of the search request. This commit
protects against these cases by replacing `took` with 1 if the elapsed time is
negative.
hmm should this be `Math.max(0,..)` I mean if the op is very fast it might be confusing to always use `1`?