[Distributed] Skip availability checks, checking if distributed is available is enough (#39899)

Author: ktoso

test/Distributed/SIL/distributed_actor_default_deinit_sil.swift

@@ -1,14 +1,11 @@
-// RUN: %target-swift-frontend -module-name default_deinit -primary-file %s -emit-sil -enable-experimental-distributed | %FileCheck %s --enable-var-scope --dump-input=fail
+// RUN: %target-swift-frontend -module-name default_deinit -primary-file %s -emit-sil -enable-experimental-distributed -disable-availability-checking | %FileCheck %s --enable-var-scope --dump-input=fail
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
-// REQUIRES: OS=macosx
-
 import _Distributed
 
 class SomeClass {}
 
-@available(macOS 12, *)
 distributed actor MyDistActor {
   let localOnlyField: SomeClass
 

test/Distributed/SIL/distributed_actor_default_init_sil.swift

@@ -1,14 +1,11 @@
-// RUN: %target-swift-frontend -module-name test -primary-file %s -emit-sil -enable-experimental-distributed | %FileCheck %s --enable-var-scope --dump-input=fail --implicit-check-not=actorReady --implicit-check-not=resignIdentity --implicit-check-not=hop_to_executor
+// RUN: %target-swift-frontend -module-name test -primary-file %s -emit-sil -enable-experimental-distributed -disable-availability-checking | %FileCheck %s --enable-var-scope --dump-input=fail --implicit-check-not=actorReady --implicit-check-not=resignIdentity --implicit-check-not=hop_to_executor
 // REQUIRES: concurrency
 // REQUIRES: distributed
 
-// REQUIRES: OS=macosx
-
 import _Distributed
 
 class SomeClass {}
 
-@available(macOS 12, *)
 distributed actor MyDistActor {
   var localOnlyField: SomeClass