Test failure on Windows ARM64

[jeroen]

See https://github.com/r-universe/duckdb/actions/runs/30353588565/job/90262612127

[eitsupi]

My understanding is that this is because DuckDB does not distribute extensions for arm64 MinGW, and this may be resolved in DuckDB v2, which is scheduled to migrate to C extension API.

In the meantime, I think the problem can be solved by specifying an extension that already uses the C API instead of the ICU extension.

[krlmlr]

Another example: https://github.com/r-universe/duckdb/actions/runs/30533304494/job/90847736895 .

@eitsupi: Do you have an example for such an extension?