Remove packageName property not defined in Java 8 (#1643)

Author: EgorkaKulikov

utbot-framework/src/main/kotlin/org/utbot/framework/assemble/AssembleModelGenerator.kt

@@ -420,7 +420,7 @@ class AssembleModelGenerator(private val basePackageName: String) {
         get() = this.isPublic || !this.isPrivate && this.packageName == basePackageName
 
     private val Constructor<*>.isVisible : Boolean
-        get() = this.isPublic || !this.isPrivate && this.declaringClass.packageName == basePackageName
+        get() = this.isPublic || !this.isPrivate && this.declaringClass.`package`.name == basePackageName
 
     /**
      * Creates setter or direct setter call to set a field.