Function S2Loop.getDistanceToBoundary
Returns the distance from the given point to the loop boundary. If the loop is empty or full, return S1Angle::Infinity() (since the loop has no boundary). "x" should be unit length.
Returns the distance from the given point to the loop boundary. If the loop is empty or full, return S1Angle::Infinity() (since the loop has no boundary). "x" should be unit length.