Validate that the shape_id matches the rest of the URL structure

[KyleAMathews]

This isn't an issue when using the official clients but when hand-constructing shape URLs or when writing a new one, it's possible to write a URL where the various parts don't match each other.

We validate already that the shape_id is the current shape_id for the url structure by returning a 409 if it's not.

We also need to validate that the shape_id is for the shape that the URL describes i.e. if a shape is defined as v1/shape/foo but then the shape_id for that shape def is applied to v1/shape/foo?where='foo=true' then we should return a 400.

Follow-up issue to #1659