Always set the endtime, allowing the span duration to be zero (#1750)
Always set the endtime, allowing the span duration to be zero (#1750)

Fixes https://github.com/open-telemetry/opentelemetry-collector/issues/1749
open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector-contrib,open-telemetry/opentelemetry-collector-contrib