`input type=checkbox` element

Pass Criteria

#1: Element is supported
#2: Correct HTML and Core Accessibility API mappings
#3: Correct Accessible Name & Description Calculation

Reference

Test ichk-001: `input type=checkbox` element

Test ichk-002: `input type=checkbox` element with `label` element

I agree

Test ichk-003: `input type=checkbox` element with implicit `label` element

I agree

Test ichk-004: `input type=checkbox` element with `disabled` attribute

I agree

Test ichk-005: `input type=checkbox` element with `required` attribute

I agree

Test ichk-006: `input type=checkbox` element with `checked` attribute

I agree

Test ichk-007: `input type=checkbox` element with `size` attribute

I disagree