Switch concurrency runtime tests to "REQUIRES: concurrency_runtime"

Rather than blanket-disabling concurrency tests when we aren't using a
just-built concurrency library, enable them whenever we have a
suitable concurrency runtime, either just-built, in the OS, or via the
back-deployment libraries.

Author: DougGregor

test/Concurrency/Runtime/actor_counters.swift

@@ -5,7 +5,7 @@
 // REQUIRES: libdispatch
 
 // rdar://76038845
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 @available(SwiftStdlib 5.5, *)

test/Concurrency/Runtime/actor_detach.swift

@@ -4,7 +4,7 @@
 // REQUIRES: concurrency
 // REQUIRES: foundation
 
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 import Foundation

test/Concurrency/Runtime/actor_init.swift

@@ -4,7 +4,7 @@
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
 
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 @available(SwiftStdlib 5.5, *)

test/Concurrency/Runtime/actor_keypaths.swift

@@ -3,7 +3,7 @@
 // REQUIRES: executable_test
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 actor Page {

test/Concurrency/Runtime/async.swift

@@ -5,7 +5,7 @@
 // REQUIRES: libdispatch
 
 // rdar://82123254
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 import Dispatch

test/Concurrency/Runtime/async_initializer.swift

@@ -5,7 +5,7 @@
 // REQUIRES: libdispatch
 
 // rdar://76038845
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 @available(SwiftStdlib 5.5, *)

test/Concurrency/Runtime/async_let_fibonacci.swift

@@ -5,7 +5,7 @@
 // REQUIRES: libdispatch
 
 // rdar://76038845
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 func fib(_ n: Int) -> Int {

test/Concurrency/Runtime/async_let_throw_completion_order.swift

@@ -5,7 +5,7 @@
 // REQUIRES: libdispatch
 
 // rdar://82123254
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 struct Bad: Error {}

test/Concurrency/Runtime/async_let_throws.swift

@@ -5,7 +5,7 @@
 // REQUIRES: libdispatch
 
 // rdar://76038845
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 struct Boom: Error {}

test/Concurrency/Runtime/async_properties_actor.swift

@@ -5,7 +5,7 @@
 // REQUIRES: libdispatch
 
 // rdar://76038845
-// UNSUPPORTED: use_os_stdlib
+// REQUIRES: concurrency_runtime
 // UNSUPPORTED: back_deployment_runtime
 
 struct Container {