Background: currently, property types are persisted separately from method mappings.
1. Our metadata lookup algorithm (LookupMethodMappings) does not take PropertyTypes into account.
This causes `ShouldNotUseCustomPropertyTranslationForUnrelatedClass` test to pick up `NSNumber.boolValue` mapping although a property `boolValue` is declared in the current class (CustomTableViewCell), and should result in an exact match.
2. Currently, both `MethodMappings` and `PropertyTypes` are used to persist property types.
We should optimally store all property types in a single location.