[NFC] Require asserts in two tests that use experimental feature flags.

Author: hborla

test/Concurrency/dynamic_checks_for_func_refs_in_preconcurrency_apis_objc.swift

@@ -1,5 +1,6 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-experimental-feature DynamicActorIsolation -emit-silgen -verify %s | %FileCheck %s
 // REQUIRES: objc_interop
+// REQUIRES: asserts
 
 import Foundation
 

test/Concurrency/sendable_objc_attr_in_type_context_swift6.swift

@@ -9,6 +9,7 @@
 // RUN:   -module-name main -I %t -verify
 
 // REQUIRES: objc_interop
+// REQUIRES: asserts
 
 //--- Test.h
 #define SWIFT_SENDABLE __attribute__((__swift_attr__("@Sendable")))