Section 180H. Except as provided in section one hundred and eighty G, no contingent claim shall share in a distribution of the assets of an insurer which has been adjudicated to be insolvent by a decree made pursuant to section six or section one hundred and eighty C, except that such claims shall be considered, if properly presented, and may be allowed to share where (a) such claim becomes absolute against the insurer on or before the last day fixed by the court for filing of proofs of claim against the assets of such insurer, or (b) there is a surplus and the proceeding in which the decree was made is thereafter conducted upon the basis that such insurer is solvent.