[WIP][Android][CoreCLR] Filter legacy TimeZone IDs using ICU if tzlookup.xml isn't available

[davidnguyen-tech]

Goal

Tries to fix #90269.

Issue summary

On Android, there are legacy TimeZones that have the same display name as non-legacy TimeZones. If developers get a list of all TimeZones and show them in UI, it can look like there are duplicate TimeZones based on the display name.

The fix we have for Android API > 25 is to use tzlookup.xml to filter out the legacy TimeZone IDs.

The problem is that for API <= 25, the tzlookup.xml file isn't available.

PR Description

• This PR tries to detect legacy TimeZones by using the ucal_getCanonicalTimeZoneID function from the ICU library.
• A canonical TimeZone ID is a "normalized" ID - basically we are able to pass a legacy ID and get the corresponding non-legacy ID (passing non-legacy ID works as well, in that case the returned value is an identity).

Problem with the PR

• Sample program

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Globalization;

public static class Program
{
    public static int Main(string[] args)
    {
        ReadOnlyCollection<TimeZoneInfo> tzCollection = TimeZoneInfo.GetSystemTimeZones();
        return 42;
    }
}

• In pal_timeZoneInfo.cs when we call ucal_getCanonicalTimeZoneID function in GlobalizationNative_GetCanonicalTimeZoneId method, the app crashes

[dotnet-policy-service]

Draft Pull Request was automatically closed for 30 days of inactivity. Please let us know if you'd like to reopen it.