Fix Collision In Generated Paging Operations

Consider this tsp:

```
interface Foo {
@route("/list")
@doc("List things with nextlink")
@convenientAPI(true)
@list
op List(): {
@pageItems
things: Thing[];

@nextLink next?: url;
};

@route("/listAll")
@doc("List things with nextlink")
@convenientAPI(true)
@list
op ListAll(): {
@pageItems
things: Thing[];

@nextLink next?: url;
};
}
```

The generator does internal renaming of operations named "List" to "GetAll". In doing so, this causes a collision in the generated code for this sample since both operations would end up having the same name.