displayedCircuit = (diagramText, ...extraGateEntries) => DisplayedCircuit.fromTextDiagram(
    new Map([
        ...COMMON_GATES.entries(),
        ...extraGateEntries
    ]),
    diagramText)
@param {!string} diagramText
@param {!Array<*>} extraGateEntries
@returns {!{circuit: !DisplayedCircuit, pts: !Array.<!Point>}}