Fix timing-dependent issue introduced into unit tests
Fix timing-dependent issue introduced into unit tests

lightstep/lightstep-tracer-javascript,lightstephq/lightstep-tracer-javascript,lightstep/lightstep-tracer-javascript,lightstephq/lightstep-tracer-javascript,lightstephq/lightstep-tracer-javascript,lightstep/lightstep-tracer-javascript