ROO-3341: Bad entity changes after field is added

This fix erroneous changes on _.java_  when  Roo modifies the file:

* `<import java.utils.*;>` --> `<import java.*;>`
* Array fields declaration `<transient String[] strings;>` --> `<transient String strings;>`
* Array parameters on constructors declaration `<Vet(String[] strings) {>` --> `<Vet(String strings) {>`