[Blazor] Add basic ICU tests

[ilonatommy]

Fixes #89406.
First merge #89926, then this one.

1. Unblock Blazor WBT ICU assets checks.
2. Rename internal LoadAllICUData -> LoadFullICUData. "All" could mean "all data files" while we meant to say "data with full locales support".
3. Fixing the problem of loading all ICU assets to runtime pack in Hybrid or Full icu mode (see ShouldFilterCandidate).

For a follow-up PR: #90018

[ghost]

Tagging subscribers to 'arch-wasm': @lewing
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Issue Details

---

1. Unblock Blazor WBT ICU assets checks.
2. Rename internal LoadAllICUData -> LoadFullICUData. "All" could mean "all data files" while it means "data with full locales support".
3. Fixing the problem of loading all ICU assets to runtime pack in Hybrid or Full icu mode (see ShouldFilterCandidate).

For a follow-up PR:

• fixing the problem with hashing when custom ICU file is used in Blazor.

Author:	ilonatommy
Assignees:	ilonatommy
Labels:	arch-wasm, area-System.Globalization, area-Build-mono
Milestone:	8.0.0

[ghost]

Tagging subscribers to this area: @dotnet/area-system-globalization
See info in area-owners.md if you want to be subscribed.

Issue Details

---

1. Unblock Blazor WBT ICU assets checks.
2. Rename internal LoadAllICUData -> LoadFullICUData. "All" could mean "all data files" while it means "data with full locales support".
3. Fixing the problem of loading all ICU assets to runtime pack in Hybrid or Full icu mode (see ShouldFilterCandidate).

For a follow-up PR:

• fixing the problem with hashing when custom ICU file is used in Blazor.

Author:	ilonatommy
Assignees:	ilonatommy
Labels:	arch-wasm, area-System.Globalization, area-Build-mono
Milestone:	8.0.0

[radical]

I'm guessing this needs a review after your other PR, that splits the tests, is merged.

[radical]

LGTM 👍 In a follow up we should expand the tests, and maybe try to re-use the ones we have for test-main.js . I will fix up our API to facilitate that.