Use latest snapshot toolchain

Author: kateinoigakukun

.github/workflows/test.yml

@@ -21,7 +21,7 @@ jobs:
               JAVASCRIPTKIT_DISABLE_TRACING_TRAIT=1
           - os: ubuntu-24.04
             toolchain:
-              download-url: https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT-SNAPSHOT-2025-12-01-a/swift-DEVELOPMENT-SNAPSHOT-2025-12-01-a-ubuntu24.04.tar.gz
+              download-url: https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a-ubuntu24.04.tar.gz
             wasi-backend: Node
             target: "wasm32-unknown-wasip1"
           - os: ubuntu-24.04
@@ -31,7 +31,7 @@ jobs:
             target: "wasm32-unknown-wasip1"
           - os: ubuntu-22.04
             toolchain:
-              download-url: https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT-SNAPSHOT-2025-12-01-a/swift-DEVELOPMENT-SNAPSHOT-2025-12-01-a-ubuntu22.04.tar.gz
+              download-url: https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a-ubuntu22.04.tar.gz
             wasi-backend: Node
             target: "wasm32-unknown-wasip1-threads"
 
@@ -152,7 +152,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: ./.github/actions/install-swift
         with:
-          download-url: https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT-SNAPSHOT-2025-09-14-a/swift-DEVELOPMENT-SNAPSHOT-2025-09-14-a-ubuntu22.04.tar.gz
+          download-url: https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a-ubuntu22.04.tar.gz
       - run: make bootstrap
       - run: ./Utilities/bridge-js-generate.sh
       - name: Check if BridgeJS generated files are up-to-date
@@ -169,7 +169,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: ./.github/actions/install-swift
         with:
-          download-url: https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT-SNAPSHOT-2026-03-09-a/swift-DEVELOPMENT-SNAPSHOT-2026-03-09-a-ubuntu22.04.tar.gz
+          download-url: https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a/swift-DEVELOPMENT-SNAPSHOT-2026-05-27-a-ubuntu22.04.tar.gz
       - uses: swiftwasm/setup-swiftwasm@v2
         id: setup-wasm32-unknown-wasip1
         with: { target: wasm32-unknown-wasip1 }

Makefile

@@ -16,7 +16,7 @@ unittest:
 		echo "SWIFT_SDK_ID is not set. Run 'swift sdk list' and pass a matching SDK, e.g. 'make unittest SWIFT_SDK_ID=<id>'."; \
 		exit 2; \
 	}
-	swift package --swift-sdk "$(SWIFT_SDK_ID)" \
+	swift package --build-system native --swift-sdk "$(SWIFT_SDK_ID)" \
 	    $(TRACING_ARGS) \
 	    --disable-sandbox \
 	    js test --prelude ./Tests/prelude.mjs -Xnode --expose-gc

Sources/JavaScriptEventLoop/JavaScriptEventLoop+ExecutorFactory.swift

@@ -63,19 +63,8 @@ extension JavaScriptEventLoop: SchedulingExecutor {
         } else if let _ = clock as? SuspendingClock {
             duration = delay as! SuspendingClock.Duration
         } else {
-            #if compiler(>=6.4)
-            // Hand-off the scheduling work to Clock implementation for unknown clocks.
-            // Clock.enqueue is only available in the development branch (6.4+).
-            clock.enqueue(
-                job,
-                on: self,
-                at: clock.now.advanced(by: delay),
-                tolerance: tolerance
-            )
-            return
-            #else
             fatalError("Unsupported clock type; only ContinuousClock and SuspendingClock are supported")
-            #endif  // #if compiler(>=6.4) (non-Embedded)
+            return
         }
         let milliseconds = Self.delayInMilliseconds(from: duration)
         self.enqueue(