Editorial: Account for [[pattern]] etc. in AdjustDateTimeStyleFormat

[ptomato]

Based on Anba's suggestion: #3273 (comment)

We pass a List of property names into AdjustDateTimeStyleFormat instead of a List of field names, so they can be compared directly with the "Property" column of the "Components of date and time formats" table. This avoids the problem of formats having other fields such as [[pattern]] and [[pattern12]] that would always conflict with the allowed fields.

[ptomato]

cc @anba

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.09%. Comparing base (978311d) to head (920fbb8).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   98.09%   98.09%           
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  Files          22       22           
  Lines       10457    10457           
  Branches     1808     1808           
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  Misses        182      182           
  Partials       17       17           

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[anba]

If allowedOptions is changed to a list of property names, then step 6.a needs to be updated from:

6.a. Set the field of formatOptions whose name is fieldName to the value of the field of baseFormat whose name is fieldName.

to:

6.a. Set formatOptions.[[<fieldName>]] to baseFormat.[[<fieldName>]].

Because I don't think it's valid to refer to an internal slot using a String value.

[ptomato]

Good catch. I think we also technically need to check if baseFormat has a [[<prop>]] field before reading it. I've updated the PR.

[anba]

Thanks!