[SE-0211] Emoji properties require ICU 57 or later

Author: benrimmington

stdlib/public/core/UnicodeScalarProperties.swift

@@ -623,6 +623,7 @@ extension Unicode.Scalar.Properties {
   ///
   /// This property corresponds to the `Emoji` property in the
   /// [Unicode Standard](http://www.unicode.org/versions/latest/).
+  @available(macOS 10.12.2, iOS 10.2, tvOS 10.1, watchOS 3.1.1, *)
   public var isEmoji: Bool {
     return _hasBinaryProperty(__swift_stdlib_UCHAR_EMOJI)
   }
@@ -639,6 +640,7 @@ extension Unicode.Scalar.Properties {
   ///
   /// This property corresponds to the `Emoji_Presentation` property in the
   /// [Unicode Standard](http://www.unicode.org/versions/latest/).
+  @available(macOS 10.12.2, iOS 10.2, tvOS 10.1, watchOS 3.1.1, *)
   public var isEmojiPresentation: Bool {
     return _hasBinaryProperty(__swift_stdlib_UCHAR_EMOJI_PRESENTATION)
   }
@@ -652,6 +654,7 @@ extension Unicode.Scalar.Properties {
   ///
   /// This property corresponds to the `Emoji_Modifier` property in the
   /// [Unicode Standard](http://www.unicode.org/versions/latest/).
+  @available(macOS 10.12.2, iOS 10.2, tvOS 10.1, watchOS 3.1.1, *)
   public var isEmojiModifier: Bool {
     return _hasBinaryProperty(__swift_stdlib_UCHAR_EMOJI_MODIFIER)
   }
@@ -661,6 +664,7 @@ extension Unicode.Scalar.Properties {
   ///
   /// This property corresponds to the `Emoji_Modifier_Base` property in the
   /// [Unicode Standard](http://www.unicode.org/versions/latest/).
+  @available(macOS 10.12.2, iOS 10.2, tvOS 10.1, watchOS 3.1.1, *)
   public var isEmojiModifierBase: Bool {
     return _hasBinaryProperty(__swift_stdlib_UCHAR_EMOJI_MODIFIER_BASE)
   }

test/stdlib/UnicodeScalarPropertiesTests.swift

@@ -83,7 +83,7 @@ UnicodeScalarPropertiesTests.test("properties.booleanProperties") {
   expectBooleanProperty(\.changesWhenNFKCCaseFolded, trueFor: "A", falseFor: "!")
 
 #if os(macOS) || os(iOS) || os(watchOS) || os(tvOS)
-  if #available(iOS 10.2, *) {
+  if #available(macOS 10.12.2, iOS 10.2, tvOS 10.1, watchOS 3.1.1, *) {
     // U+2708 AIRPLANE
     expectBooleanProperty(\.isEmoji, trueFor: "\u{2708}", falseFor: "A")
     // U+231A WATCH