Android/WASM workflows can build with mismatched toolchain + SDK versions #256
Description
It appears that in some cases it's possible for the Android/WASM swift package test workflows to build against an Android/WASM SDK that does not match our toolchain version. For example, see https://github.com/swiftlang/swift-foundation/actions/runs/23912627888/job/69738273919?pr=1871:
** Found latest main wasm-sdk snapshot: swift-DEVELOPMENT-SNAPSHOT-2026-04-01-a
** Found wasm-sdk checksum: 5ae95d926686...
** Found wasm-sdk download filename: swift-DEVELOPMENT-SNAPSHOT-2026-04-01-a_wasm.artifactbundle.tar.gz
** ✅ Found Swift snapshot tag in /.swift_tag: swift-DEVELOPMENT-SNAPSHOT-2026-03-16-a
** Installing Swift toolchain to match Wasm Swift SDK snapshot: swift-DEVELOPMENT-SNAPSHOT-2026-04-01-a
This seems to be resulting in build failures due to a "bad" SDK when building swift-foundation