[Concurrency] Fix potential ABI breakages.

Fix a couple of potential ABI breaks.  Also add the new functions and types
to the baseline lists.

rdar://141348916

Author: al45tair

stdlib/public/Concurrency/Executor.swift

@@ -101,14 +101,14 @@ public protocol Executor: AnyObject, Sendable {
   #endif // !$Embedded
 }
 
-@available(SwiftStdlib 6.2, *)
 extension Executor {
+  @available(SwiftStdlib 6.2, *)
   @usableFromInline
   internal var _isComplexEquality: Bool { false }
 }
 
-@available(SwiftStdlib 6.2, *)
 extension Executor where Self: Equatable {
+  @available(SwiftStdlib 6.2, *)
   @usableFromInline
   internal var _isComplexEquality: Bool { true }
 }
@@ -594,15 +594,16 @@ public func _createExecutors<F: ExecutorFactory>(factory: F.Type) {
   Task._defaultExecutor = factory.defaultExecutor
 }
 
-@available(SwiftStdlib 6.2, *)
 extension MainActor {
+  @available(SwiftStdlib 6.2, *)
   static var _executor: (any MainExecutor)? = nil
 
   /// The main executor, which is started implicitly by the `async main`
   /// entry point and owns the "main" thread.
   ///
   /// Attempting to set this after the first `enqueue` on the main
   /// executor is a fatal error.
+  @available(SwiftStdlib 6.2, *)
   public static var executor: any MainExecutor {
     if _executor == nil {
       _executor = PlatformExecutorFactory.mainExecutor
@@ -611,15 +612,16 @@ extension MainActor {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
 extension Task where Success == Never, Failure == Never {
+  @available(SwiftStdlib 6.2, *)
   static var _defaultExecutor: (any TaskExecutor)? = nil
 
   /// The default or global executor, which is the default place in which
   /// we run tasks.
   ///
   /// Attempting to set this after the first `enqueue` on the global
   /// executor is a fatal error.
+  @available(SwiftStdlib 6.2, *)
   public static var defaultExecutor: any TaskExecutor {
     if _defaultExecutor == nil {
       _defaultExecutor = PlatformExecutorFactory.defaultExecutor
@@ -628,10 +630,10 @@ extension Task where Success == Never, Failure == Never {
   }
 }
 
-@available(SwiftStdlib 6.2, *)
 extension Task where Success == Never, Failure == Never {
   /// Get the current executor; this is the executor that the currently
   /// executing task is executing on.
+  @available(SwiftStdlib 6.2, *)
   @_unavailableInEmbedded
   public static var currentExecutor: (any Executor)? {
     if let taskExecutor = _getPreferredTaskExecutor().asTaskExecutor() {

stdlib/public/Concurrency/GlobalConcurrentExecutor.swift

@@ -54,7 +54,7 @@ internal final class _DefaultGlobalConcurrentExecutor: TaskExecutor {
   private init() {}
 
   public func enqueue(_ job: consuming ExecutorJob) {
-    _enqueueJobGlobal(UnownedJob(job))
+    _enqueueJobGlobal(UnownedJob(job)._context)
   }
 
   public func asUnownedTaskExecutor() -> UnownedTaskExecutor {

stdlib/public/Concurrency/Task.swift

@@ -1253,7 +1253,7 @@ extension Task where Success == Never, Failure == Never {
       let job = _taskCreateNullaryContinuationJob(
           priority: Int(Task.currentPriority.rawValue),
           continuation: continuation)
-      _enqueueJobGlobalDirect(job)
+      _enqueueJobGlobal(job)
     }
   }
 }
@@ -1412,22 +1412,24 @@ func getJobFlags(_ task: Builtin.NativeObject) -> JobFlags
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("swift_task_enqueueGlobal")
 @usableFromInline
-func _enqueueJobGlobal(_ task: UnownedJob)
+func _enqueueJobGlobal(_ task: Builtin.Job)
 
+@available(SwiftStdlib 6.2, *)
 @usableFromInline
-func _enqueueJobGlobalDirect(_ task: Builtin.Job) {
-  if #available(SwiftStdlib 5.9, *) {
-    _enqueueJobGlobal(UnownedJob(context: task))
-  } else {
-    // Shouldn't ever get here
-    Builtin.unreachable()
-  }
+func _enqueueJobGlobal(_ task: UnownedJob) {
+  _enqueueJobGlobal(task._context)
 }
 
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("swift_task_enqueueGlobalWithDelay")
 @usableFromInline
-func _enqueueJobGlobalWithDelay(_ delay: UInt64, _ task: UnownedJob)
+func _enqueueJobGlobalWithDelay(_ delay: UInt64, _ task: Builtin.Job)
+
+@available(SwiftStdlib 6.2, *)
+@usableFromInline
+func _enqueueJobGlobalWithDelay(_ delay: UInt64, _ task: UnownedJob) {
+  return _enqueueJobGlobalWithDelay(delay, task._context)
+}
 
 @available(SwiftStdlib 5.7, *)
 @_silgen_name("swift_task_enqueueGlobalWithDeadline")