MandatoryGenericSpecializer: run optimizations in a loop
MandatoryGenericSpecializer: run optimizations in a loop

To avoid phase ordering problems of the involved optimizations, iterate until we reach a fixed point.

benlangmuir/swift,glessard/swift,JGiola/swift,glessard/swift,JGiola/swift,apple/swift,apple/swift,apple/swift,roambotics/swift,glessard/swift,apple/swift,roambotics/swift,benlangmuir/swift,benlangmuir/swift,JGiola/swift,roambotics/swift,roambotics/swift,benlangmuir/swift,glessard/swift,JGiola/swift,apple/swift,benlangmuir/swift,roambotics/swift,apple/swift,glessard/swift,roambotics/swift,JGiola/swift,glessard/swift,benlangmuir/swift,JGiola/swift