Constructor names are not compared

``` java
Truth.assertAbout(JavaSourcesSubjectFactory.javaSources())
.that(givenJavaFile)
.processedWith(someProcessor)
.compilesWithoutError()
.and()
.generatesSources(expectedJavaFile);
```

Expected and generated constructor names are not compared.
Obviously it will fail later at generated source compilation if name is wrong, but it would be nice to detect it in generated sources comparison to make tests fail if such error occurs.

Generated:

``` java
public class Generated {
public Generated() {
}
}
```

Expected:

``` java
public class Generated {
public GeneratedWithBadName() {
}
}
```

With the previous examples, comparison does not fail.