Upstream trivial diffs

withSerializationContext needs to be exposed to tests, and BuildService.run needs to build and do so without warnings regardless of whether USE_STATIC_PLUGIN_INITIALIZATION is set.

Author: jakepetroules

Sources/SWBBuildService/BuildServiceEntryPoint.swift

@@ -95,7 +95,7 @@ extension BuildService {
     ///
     /// Called directly from the exported C entry point `swiftbuildServiceEntryPoint` for in-process connections, or from `BuildService.main()` (after some basic file descriptor setup) for out-of-process connections.
     fileprivate static func run(inputFD: FileDescriptor, outputFD: FileDescriptor, connectionMode: ServiceHostConnectionMode, pluginsDirectory: URL?, arguments: [String], pluginLoadingFinished: () throws -> Void) async throws {
-        let pluginManager = await { @PluginExtensionSystemActor in
+        let pluginManager = try await { @PluginExtensionSystemActor () async throws in
             // Create the plugin manager and load plugins.
             let pluginManager = PluginManager(skipLoadingPluginIdentifiers: [])
 

Sources/SWBTaskExecution/BuildDescription.swift

@@ -1398,7 +1398,7 @@ package final class TaskActionRegistry: Sendable {
         implementations = try TaskActionExtensionPoint.taskActionImplementations(pluginManager: pluginManager)
     }
 
-    func withSerializationContext<T>(_ block: () throws -> T) rethrows -> T {
+    @_spi(Testing) public func withSerializationContext<T>(_ block: () throws -> T) rethrows -> T {
         try TaskAction.$taskActionImplementations.withValue(implementations) {
             try block()
         }