Arlington cybersecurity start-up ThreatConnect said Tuesday that it has raised $16 million from investors, led by the corporate venture capital arm of SAP’s North American subsidiary in Rockville. The next morning just down the road in Sterling, Va., a similarly-named start-up called ThreatQuotient said it raised $10.2 million, led by prolific technology investor New Enterprise Associates. A few weeks ago Arlington-based Trustar announced a $2 million in seed funding.