A bond, covenant, or agreement made for a valuable consideration by a testator, to convey any property devised or bequeathed in any last will previously made, shall not be deemed a revocation of such previous devise or bequest, but such property shall pass by the devise or bequest, subject to the same remedies on such bond, covenant, or agreement, for specific performance or otherwise, against devisees or legatees, as might be had by law against the heirs of the testator, or his next of kin, if the same had descended to them.