Apply @_unsafeInheritExecutor to with(Throwing)TaskGroup.

Fixes rdar://98461630.

Author: DougGregor

stdlib/public/Concurrency/TaskGroup.swift

@@ -65,6 +65,7 @@ import Swift
 /// use the `withThrowingTaskGroup(of:returning:body:)` method instead.
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lF")
+@_unsafeInheritExecutor
 @inlinable
 public func withTaskGroup<ChildTaskResult, GroupResult>(
   of childTaskResultType: ChildTaskResult.Type,
@@ -157,6 +158,7 @@ public func withTaskGroup<ChildTaskResult, GroupResult>(
 /// or to let the group rethrow the error.
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lF")
+@_unsafeInheritExecutor
 @inlinable
 public func withThrowingTaskGroup<ChildTaskResult, GroupResult>(
   of childTaskResultType: ChildTaskResult.Type,

test/Concurrency/unsafe_inherit_executor_lib.swift

@@ -0,0 +1,16 @@
+// RUN: %target-swift-frontend -typecheck -verify -disable-availability-checking %s -strict-concurrency=complete
+
+actor A {
+  func g() { }
+  func h() throws { }
+  
+  func f() async throws {
+    await withTaskGroup(of: Int.self, returning: Void.self) { group in
+      g()
+    }
+
+    try await withThrowingTaskGroup(of: Int.self, returning: Void.self) { group in
+      try h()
+    }
+  }
+}