Fix testcase now that we get warnings instead of errors

Author: DougGregor

test/ClangImporter/objc_async.swift

@@ -4,6 +4,7 @@
 // REQUIRES: concurrency
 import Foundation
 import ObjCConcurrency
+// expected-remark@-1{{add '@preconcurrency' to suppress 'Sendable'-related warnings from module 'ObjCConcurrency'}}
 
 @available(SwiftStdlib 5.5, *)
 @MainActor func onlyOnMainActor() { }
@@ -322,6 +323,7 @@ func check() async {
   _ = await BazFrame(size: 0)
 }
 
+@available(SwiftStdlib 5.5, *)
 func testSender(
   sender: NXSender,
   sendableObject: SendableClass,
@@ -333,7 +335,7 @@ func testSender(
   nonSendableGeneric: GenericObject<SendableClass>,
   ptr: UnsafeMutableRawPointer,
   stringArray: [String]
-) {
+) async {
   sender.sendAny(sendableObject)
   sender.sendAny(nonSendableObject)
   // expected-warning@-1 {{conformance of 'NonSendableClass' to 'Sendable' is unavailable}}
@@ -352,22 +354,22 @@ func testSender(
 
   sender.sendProto(sendableProtos)
   sender.sendProto(nonSendableProtos)
-  // expected-error@-1 {{argument type 'any LabellyProtocol & ObjCClub' does not conform to expected type 'Sendable'}}
-  // FIXME(rdar://89992095): Should be a warning because we're in -warn-concurrency
+  // expected-warning@-1 {{type 'any LabellyProtocol & ObjCClub' does not conform to the 'Sendable' protocol}}
 
   sender.sendProtos(sendableProtos)
   sender.sendProtos(nonSendableProtos)
-  // expected-error@-1 {{argument type 'any LabellyProtocol & ObjCClub' does not conform to expected type 'Sendable'}}
-  // FIXME(rdar://89992095): Should be a warning because we're in -warn-concurrency
+  // expected-warning@-1 {{type 'any LabellyProtocol & ObjCClub' does not conform to the 'Sendable' protocol}}
 
   sender.sendAnyArray([sendableObject])
   sender.sendAnyArray([nonSendableObject])
-  // expected-warning@-1 {{conformance of 'NonSendableClass' to 'Sendable' is unavailable}}
+  // expected-warning@-1 {{conformance of 'NonSendableClass' to 'Sendable' is unavailable; this is an error in Swift 6}}
 
   sender.sendGeneric(sendableGeneric)
+  // expected-warning@-1{{type 'GenericObject<SendableClass>' does not conform to the 'Sendable' protocol}}
+  // FIXME: Shouldn't warn
+
   sender.sendGeneric(nonSendableGeneric)
-  // expected-error@-1 {{argument type 'GenericObject<SendableClass>' does not conform to expected type 'Sendable'}}
-  // FIXME(rdar://89992095): Should be a warning because we're in -warn-concurrency
+  // expected-warning@-1 {{type 'GenericObject<SendableClass>' does not conform to the 'Sendable' protocol}}
 
   sender.sendPtr(ptr)
   sender.sendStringArray(stringArray)