Merge pull request #24921 from mikeash/existentials-objc-test-disable-testing-os-libraries

[Test] Disable existentials_objc.swift when testing against OS libraries.

Author: mikeash

validation-test/Reflection/existentials_objc.swift

@@ -1,7 +1,8 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift -lswiftSwiftReflectionTest %s -o %t/existentials_objc
 // RUN: %target-codesign %t/existentials_objc
-// RUN: %target-run %target-swift-reflection-test %t/existentials_objc | %FileCheck %s
+// RUN: %target-run %target-swift-reflection-test %t/existentials_objc > %t.txt
+// RUN: grep SkipTheTest %t.txt || %FileCheck %s < %t.txt
 
 // REQUIRES: objc_interop
 // REQUIRES: executable_test
@@ -15,15 +16,21 @@ import Foundation
 
 import SwiftReflectionTest
 
-// Imported class wrapped in AnyObject
-
-// CHECK: Type reference:
-// CHECK: (objective_c_class name=NSObject)
-reflect(object: NSObject())
-
-// Tagged pointer wrapped in AnyObject
-// CHECK: Type reference:
-// CHECK: (objective_c_class name=__NSCFNumber)
-reflect(object: NSNumber(123))
+if #available(macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, *) {
+  // Imported class wrapped in AnyObject
+
+  // CHECK: Type reference:
+  // CHECK: (objective_c_class name=NSObject)
+  reflect(object: NSObject())
+
+  // Tagged pointer wrapped in AnyObject
+  // CHECK: Type reference:
+  // CHECK: (objective_c_class name=__NSCFNumber)
+  reflect(object: NSNumber(123))
+} else {
+  // The Swift 5.0 libraries don't support this test.
+  class SkipTheTest {}
+  reflect(object: SkipTheTest())
+}
 
 doneReflecting()