Ensure Primary Constructor Parameter Member Generation Coverage

* When a primary constructor parameter is used, the compiler captures the constructor parameter in a **private field** with a compiler-generated name.
If a primary constructor parameter isn't used in the body of the type, **no private field is captured**. (That rule prevents accidentally allocating two copies of a primary constructor parameter that's passed to a base constructor.)
* If the type includes the record modifier, the compiler instead synthesizes a **public property** with the same name as the primary constructor parameter.
* For record class types, if a primary constructor parameter uses the same name as a base primary constructor, that property is a public property of the base record class type. It isn't duplicated in the derived record class type. These properties aren't generated for non-record types.
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