fix a few test assertions

Author: ktoso

test/Distributed/distributed_actor_conditionally_implicitly_codable.swift

@@ -31,11 +31,11 @@ func test_NotAtAll_NoImplicit(_ actor: SerReqNotCodable) {
 
 // ==== ------------------------------------------------------------------------
 
-distributed actor NotAtAll_NothingCodable { // expected-error{{type 'NotAtAll_NothingCodable' does not conform to protocol 'Decodable'}}
+distributed actor NotAtAll_NothingCodable {
   typealias ActorSystem = FakeIdIsNotCodableActorSystem
 }
 func test_NotAtAll_NoImplicit(_ actor: NotAtAll_NothingCodable) {
-  let _: any Codable = actor
+  let _: any Codable = actor // expected-error{{value of type 'NotAtAll_NothingCodable' does not conform to specified type 'Decodable'}}
 
   // no implicit conformance
   let _: any CustomSerializationProtocol = actor // expected-error{{value of type 'NotAtAll_NothingCodable' does not conform to specified type 'CustomSerializationProtocol'}}

test/Distributed/distributed_actor_system_missing.swift

@@ -10,10 +10,7 @@ distributed actor DA {
   // expected-error@-1{{distributed actor 'DA' does not declare ActorSystem it can be used with}}
   // expected-error@-2 {{type 'DA' does not conform to protocol 'DistributedActor'}}
 
-  // Since synthesis would have failed due to the missing ActorSystem:
-  // expected-error@-5{{type 'DA' does not conform to protocol 'Decodable'}}
-
-  // expected-note@-7{{you can provide a module-wide default actor system by declaring:}}
+  // expected-note@-4{{you can provide a module-wide default actor system by declaring:}}
 
   // Note to add the typealias is diagnosed on the protocol:
   // _Distributed.DistributedActor:3:20: note: diagnostic produced elsewhere: protocol requires nested type 'ActorSystem'; do you want to add it?
@@ -26,8 +23,6 @@ distributed actor DA {
 distributed actor Server { // expected-error 2 {{distributed actor 'Server' does not declare ActorSystem it can be used with}}
   // expected-error@-1 {{type 'Server' does not conform to protocol 'DistributedActor'}}
   // expected-note@-2{{you can provide a module-wide default actor system by declaring:}}
-  // expected-error@-3{{type 'Server' does not conform to protocol 'Encodable'}}
-  // expected-error@-4{{type 'Server' does not conform to protocol 'Decodable'}}
   typealias ActorSystem = DoesNotExistDataSystem
   // expected-error@-1{{cannot find type 'DoesNotExistDataSystem' in scope}}
   typealias SerializationRequirement = any Codable

test/Distributed/distributed_actor_system_missing_type_no_crash.swift

@@ -12,7 +12,6 @@ distributed actor Fish {
   // expected-error@-2{{distributed actor 'Fish' does not declare ActorSystem it can be used with}}
   // expected-error@-3{{type 'Fish' does not conform to protocol 'DistributedActor'}}
   // expected-note@-4{{you can provide a module-wide default actor system by declaring:\ntypealias DefaultDistributedActorSystem = <#ConcreteActorSystem#>}}
-  // expected-error@-5{{type 'Fish' does not conform to protocol 'Decodable'}}
 
   distributed func tell(_ text: String, by: Fish) {
     // What would the fish say, if it could talk?

test/Distributed/distributed_protocols_distributed_func_serialization_requirements.swift

@@ -53,7 +53,6 @@ distributed actor ProtocolWithChecksSeqReqDA_MissingSystem: ProtocolWithChecksSe
   // expected-error@-4{{distributed actor 'ProtocolWithChecksSeqReqDA_MissingSystem' does not declare ActorSystem it can be used with}}
   //
   // expected-error@-6{{type 'ProtocolWithChecksSeqReqDA_MissingSystem' does not conform to protocol 'DistributedActor'}}
-  // expected-error@-7{{type 'ProtocolWithChecksSeqReqDA_MissingSystem' does not conform to protocol 'Decodable'}}
 
   // Entire conformance is doomed, so we didn't proceed to checking the functions; that's fine
   distributed func testAT() async throws -> NotCodable { .init() }