ref to method ref to avoid compile error

Given:
public static Function<String, Integer> useTypeReferenceOnLocalType() {
    return numberInText -> dummy(numberInText);
}

When:
Applying "Simplify lambda expression" cleanup...

Actual:
public static Function<String, Integer> useTypeReferenceOnLocalType() {
    return this::dummy;
}

Expected:
public static Function<String, Integer> useTypeReferenceOnLocalType() {
    return E::dummy;
}

Change-Id: I7d5c9d7fa452026777983e2d6296e86fd2750d54
Signed-off-by: Fabrice Tiercelin <fabrice.tiercelin@yahoo.fr>