Use native classes in routing tests that are not about classic classes

[NullVoxPopuli-ai-agent]

Tests about routing, locations and the router service stop using the classic object model. Only test files and one test harness file change.

Why this is a separate PR

This PR does for classic classes what #21690 does for A().

#21673 deprecates .extend(), reopen() and reopenClass() (RFC 1117). The spike #21674 deprecates EmberObject, its get and set methods, and computed (RFC 1234). A test that is about one of those APIs keeps it, expects the deprecation, and has a removal guard. A test that is about a feature that stays must not use them.

The 13 files here are in the second group. This PR has no dependency on a deprecation, so it can merge first. After it merges, these files drop out of #21673.

Changes

Route.extend({ ... })            class extends Route { ... }
Router.reopen({ location })      this.subclass('router:main', (Router) => class extends Router { ... })
instance.reopen({ method })      instance.method = ...
Class.reopenClass({ compare })   static compare
router.get('location.path')      router.location.path
controller.set('page', 2)        set(controller, 'page', 2)
EmberObject fixture              plain class
@computed get x()                get x()

• ember/tests/routing/router_service_test/: basic_test, recognize_test, transitionTo_test
• ember/tests/routing/query_params_test/: model_dependent_state_with_query_params_test, overlapping_query_params_test
• ember/tests/routing/decoupled_basic_test
• @ember/routing/tests/location/: history_location_test, none_location_test
• @ember/routing/tests/system/dsl_test
• attrs-lookup-test, @ember/utils/tests/compare_test: only .extend() and reopenClass() go. These tests are about classic components and about EmberObject values.
• @ember/utils/tests/type_of_test: the assertion for a classic class stays, and a new assertion covers a native class.

New in the test harness: subclass(specifier, build) on the application test case. The registry caches a class after the first lookup, so the helper removes the registration before it adds the subclass.

Not in this PR

• init on Route, Router and location subclasses stays. HistoryLocation#init sets baseURL and location, so a class field cannot replace an init that sets them after super.init(). The replacement for init is an open decision in Spike: deprecate EmberObject (RFC 1234) #21674.
• model_dependent_state_with_query_params_test.js still calls A(). Use native and tracked arrays in tests that are not about Ember arrays #21690 changes those lines. The two PRs merge without a conflict.

Test results

Local runs of the full suite on this branch. The number of tests is the same as on main.

default                         9272 pass, 18 skip, 0 fail
ALL_DEPRECATIONS_ENABLED=true   9272 pass, 18 skip, 0 fail

tsc --noEmit, eslint and prettier --check pass on the changed files.

🤖 Generated with Claude Code