Fixing the issues 392440 and 434912

The [https://bugs.eclipse.org/bugs/show_bug.cgi?id=392440 issue 392440] concerns the lake of the ```this``` keyword before the object's fields in the ```JvmTypesBuilder.toHashCodeMethod()```.

The [https://bugs.eclipse.org/bugs/show_bug.cgi?id=434912 issue 434912] concerns the lake of the ```this``` keyword before the object's fields in the ```JvmTypesBuilder.toEqualsMethod()```.