Introduce implicit statements simplification phase, specifically:
- A implicit `return` simplification: `return` statements in `void`
type functions, which are not followed by any other scope, can be
omitted.
- A implicit `continue` simplification: `continue` statements whose
fallthrough leads directly to the end of the cycle scope (i.e., to
execute another iteration of the enclosing loop), can be omitted.
In order to avoid the printing of the implicit `return`, we need an
additional `emitReturn` parameter in the `emitBasicBlock` method of the
`CCodeGenerator` class.
Alessandro Di Federico