Fix form's named property behavior

[duonglaiquang]

This PR does the following

Fix form's named property to use past names map per HTML spec.

Problem

The form's named property getter (form.xyz) incorrectly tracks name history on individual elements via the FormFieldWithNameHistory interface. Each form element (input, button, select, etc.) stores its originalName and all newNames, making the element permanently accessible through every name it has ever had.

Per the spec, a form should maintain a past names map at the form level, not on individual elements. The map is populated only when form.xyz resolves to a single element, and entries are invalidated when the element's form owner changes.

Reproducing

// Setup: <form id="f"><input name="foo"></form>

// Rename via form.elements — should NOT register in past names map
f.elements.foo.name = 'bar';
console.log(f.foo); // Expected: undefined — Actual (HtmlUnit): [object HTMLInputElement]
console.log(f.bar === f.foo); // Expected: false — Actual (HtmlUnit): true

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[rbri]

@duonglaiquang thanks a lot

[rbri]

Have mentioned you as author on all changed files