Add REQUIRES: asserts to a test that needs asserts.

Author: gottesmm

test/Concurrency/sending_conditional_suppression.swift

@@ -1,8 +1,8 @@
 // RUN: %empty-directory(%t)
-
 // RUN: %target-swift-frontend -enable-upcoming-feature SendingArgsAndResults -swift-version 5 -enable-library-evolution -module-name test -emit-module -o %t/test.swiftmodule -emit-module-interface-path - -target %target-swift-5.1-abi-triple -Xllvm -swift-ast-printer-number-suppression-checks %s | %FileCheck %s
 
 // REQUIRES: swift_feature_SendingArgsAndResults
+// REQUIRES: asserts
 
 public class NonSendableKlass {}