compactDisplay in PluralRules should only be set if notation is "compact"

[FrankYFTang]

I found this while I try to implement PR 989 and 1019
see https://chromium-review.googlesource.com/c/v8/v8/+/7047379

In https://github.com/tc39/ecma402/pull/1019/files we added "compactDisplay" for PluralRules.

But somehow we unconditionally call

Set pluralRules.[[CompactDisplay]] to compactDisplay.

If we look at the NumberFormat, we set it only if notation is "compact"

18. If notation is "compact", then
    a. Set numberFormat.[[CompactDisplay]] to compactDisplay.

So if we have the following code

let nf1 = new Intl.NumberFormat("fr-FR", { compactDisplay: "long" })
let nf2= new Intl.NumberFormat("fr-FR", { notation:"standard", compactDisplay: "long" })
let nf3 = new Intl.NumberFormat("fr-FR", { notation:"scientific", compactDisplay: "long" })
let nf4 = new Intl.NumberFormat("fr-FR", { notation:"engineering", compactDisplay: "long" })

let p1 = new Intl.PluralRules("fr-FR", { compactDisplay: "long" })
let p2= new Intl.PluralRules("fr-FR", { notation:"standard", compactDisplay: "long" })
let p3 = new Intl.PluralRules("fr-FR", { notation:"scientific", compactDisplay: "long" })
let p4 = new Intl.PluralRules("fr-FR", { notation:"engineering", compactDisplay: "long" })

then nf1.resolvedOptions().compactDisplay is undefined as well as nf2, nf3, nf4
but by the current spec p1.resolvedOptions().compactDisplay is somehow "long", as well as p2, p3, p4

I think compactDisplay for p1... p4 should also be undefined. It will make the v8 implementation much easier

[FrankYFTang]

@sffc @ben-allen @gibson042 @anba

[FrankYFTang]

I already propose #1032 but I have no right to merge that PR