Add referrer capability to the test resolver

[mixonic]

Extracted from #16158

This patch improves the the test-mode resolver used across the suite. It allows the addition of a resolution with a referrer. For example:

  moduleFor('Registry module unification', class extends AbstractTestCase {
    ['@test The registry can pass a referrer to the resolver'](assert) {
      let PrivateComponent = factory();
      let type = 'component';
      let name = 'my-input';
      let specifier = `${type}:${name}`;
      let referrer = 'template:routes/application';

      let resolver = new ModuleBasedTestResolver();
      resolver.add({specifier, referrer}, PrivateComponent); // <- added with the fullName, and an expected referrer
      let registry = new Registry({ resolver });

      assert.strictEqual(
        registry.resolve(specifier, { referrer }),
        PrivateComponent,
        'The correct factory was provided'
      );
      assert.strictEqual(
        registry.resolve(specifier, { referrer }),
        PrivateComponent,
        'The correct factory was provided again'
      );
    }
  });