intl402/DateTimeFormat/prototype/formatRangeToParts/date-same-returns-single-date.js is using `formatRange` and `format`.
Fix this test to use `formatRangeToParts` and `formatToParts` since it is the intention of this test.
This patch adds additional tests to intl402/DateTimeFormat/prototype/formatRangeToParts/date-same-returns-single-date.js and
intl402/DateTimeFormat/prototype/formatRange/date-same-returns-single-date.js. The new test uses two dates that are practially-equal,
and ensures the implementation uses `format` or `formatToParts` by detecting they are practically-equal.