[Test] Note that test requires observation to be built

DougGregor · DougGregor · commit 9b88f993a993 · 2023-05-30T17:34:57.000-07:00
diff --git a/test/ModuleInterface/Observable.swift b/test/ModuleInterface/Observable.swift
@@ -4,6 +4,7 @@
 // RUN: %FileCheck %s < %t/Library.swiftinterface
 
 // REQUIRES: swift_swift_parser
+// REQUIRES: observation
 
 import _Observation
 
