[PLAT-4556] : test toderivative for CouponArithmeticAverageONDefinition.
[PLAT-4555] : test toderivative for CouponArithmeticAverageONSpreadDefinition.
[PLAT-4554] : test toderivative for CouponArithmeticAverageONSpreadSimplifiedDefinition.