[wasm][icu] ICU files sharding + custom icu data loading for WASM

[ilonatommy]

• Allows choosing ICU file in .csproj, including custom ICU files.
• Adds an instruction how to build custom ICU.
• Works only for Wasm Console / Wasm Browser. Blazor is not touched and setting any of the new flags does not have any effect on Blazor - tested on the aspnetcore's sample.
• We have no tests for NodeJS under Windows because it's hard to change locale in Windows only for test purposes. We do not have them under Linux because helix is using MsBuild for building WBT and MsBuild is automatically overwriting any locale settings we try to force. Manual test pass.

Future work:

• Automatic tools for creating custom icu pack, so that manual running of icu build would not be necessary.

[ghost]

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Issue Details

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Author:	ilonatommy
Assignees:	ilonatommy
Labels:	arch-wasm
Milestone:	8.0.0

[ilonatommy]

How can it fail when my branch does not even have this file?

@azure-pipelinesazure-pipelines
/ dotnet-linker-tests (Build browser-wasm linux release Runtime_Release)
src/tasks/WasmAppBuilder/wasi/WasiAppBuilder.cs#L20
src/tasks/WasmAppBuilder/wasi/WasiAppBuilder.cs(20,61): error CS0103: (NETCORE_ENGINEERING_TELEMETRY=Build) The name 'IcuDataFileName' does not exist in the current context

https://github.com/ilonatommy/runtime/tree/wasm-browser-basic-sharding/src/tasks/WasmAppBuilder/wasi

edit:
it's because CI is merging main to the PR's branch and then building the result, that explains the error.

[radical]

/azp run runtime-wasm-optional

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[radical]

This was a lot of work! Thank you, and excellent job! 👍

[ilonatommy]

/azp run runtime-wasm-non-libtests

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[ilonatommy]

/azp run runtime-wasm-optional

The failures

src/libraries/Common/tests/System/TestILAssembly/TestILAssembly.ilproj(0,0): error NU1101: (NETCORE_ENGINEERING_TELEMETRY=Restore) Unable to find package runtime.wasi-x64.microsoft.netcore.ilasm. No packages exist with this id in source(s): dotnet-eng, dotnet-libraries, dotnet-public, dotnet-tools, dotnet7, dotnet7-transport, dotnet8, dotnet8-transport

are not connected.