Add availability to a few new tests (swiftlang#40048)

its available, not availabile

Author: Azoy

stdlib/private/StdlibUnicodeUnittest/StdlibUnicodeUnittest.swift

@@ -74,10 +74,11 @@ public struct NormalizationTest {
 // file API...
 #if _runtime(_ObjC)
 import Foundation
-public let normalizationTests: [NormalizationTest] = {
+
+func readInputNormalizationTest(index: Int) -> [NormalizationTest] {
   var tests = [NormalizationTest]()
 
-  let file = CommandLine.arguments[2]
+  let file = CommandLine.arguments[index]
   let fileURL = URL(fileURLWithPath: file)
 
   let fileContents = try! String(contentsOf: fileURL) + "" // go faster
@@ -111,7 +112,13 @@ public let normalizationTests: [NormalizationTest] = {
   }
 
   return tests
-}()
+}
+
+// Older version of stdlib with ICU and supporting Unicode 11
+public let normalizationTests = readInputNormalizationTest(index: 2)
+
+// Native normalization in stdlib supporting Unicode 14
+public let normalizationTests14 = readInputNormalizationTest(index: 3)
 #endif
 
 public struct UTFTest {