`DecimalLiteralRepresentation` simplification
`DecimalLiteralRepresentation` simplification

Remove recalculation of literal value.

graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust