ICU-22920 Fix raw type warnings in icu4j core tests

[mihnita]

To make the review easier this only fixes one kind of warning:
XYZ is a raw type. References to generic type XYZ should be parameterized.

This PR removes about 440 warnings.

Only fixed the warnings in tests, leaving the main code untouched.

The non-test code might needs a bit more care.
Some might be implementation details, private methods / members, easy to change.
But some might affect public APIs

---

There is also a leftover class in tests that need fixing.

LocaleAliasTest fails if I fix it, because it is already broken, but no tests run.

There is a generic (typeless) Map, initialized with some String (key) => Strings (value).

Later on there are get(ULocale) calls, which return null, and that test case if skipped.
So no test is executed, because in fact all test cases are skipped.

If I fix the type of the map to <ULocale, ULocale> (as it should be), then the real tests are executed and some are failing.

Checklist

• Required: Issue filed: ICU-22920
• Required: The PR title must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Required: The PR description must include the link to the Jira Issue, for example by completing the URL in the first checklist item
• Required: Each commit message must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Issue accepted (done by Technical Committee after discussion)
• Tests included, if applicable
• API docs and/or User Guide docs changed or added, if applicable

[jira-pull-request-webhook]

Hooray! The files in the branch are the same across the force-push. 😃

~ Your Friendly Jira-GitHub PR Checker Bot