Update validation suite to use initializers for literal conformances.

Swift SVN r22079

validation-test/stdlib/UnicodeTrie.swift.gyb

@@ -71,6 +71,11 @@ grapheme_cluster_break_tests = \
 // The most simple subclass of NSString that CoreFoundation does not know
 // about.
 class NonContiguousNSString : NSString {
+  override init() {
+    _value = []
+    super.init()
+  }
+
   required init(coder aDecoder: NSCoder) {
     fatalError("don't call this initializer")
   }