Support BSON types when debugging using the chrome debugger

[kraenhansen]

In the current state, creating an object with a property (_id in the error message below) of type BSON ObjectId will fail when the app is running in Chrome debugging mode, with the following error message:

ClassName._id must be of type 'objectId', got 'object' ([object Object])

The current implementation is depending on a _bson, _Decimal128 and _ObjectId constants being patched onto the Realm constructor in a couple of places:

• js_types.hpp / create_bson_type
• js_types.hpp / to_bson
• jsc_value.cpp / from_decimal128
• jsc_value.cpp / from_object_id

When reading a property of type ObjectId, users will also experience:

Error: _ObjectId must be of type 'constructor', got (undefined)

This constant is never set when running in chrome debugging mode.