#69204 introduced the Int128 and UInt128 types and included interop tests validating they are passed correctly to/from native.

However, they are currently disabled for Mono as are a large number of the Interop/PInvoke/* tests. These tests need to be enabled for Mono to ensure that these types work correctly in Interop scenarios.

The other Interop/PInvoke/* tests should likely be looked at as well since a majority of them currently appear to be disabled. See https://github.com/dotnet/runtime/blob/main/src/tests/issues.targets#L1716-L1772 under https://github.com/dotnet/runtime/blob/main/src/tests/issues.targets#L1446-L1447