Add dart analyzer test suite 'analyze_library' that fails if we

sdk/lib/crypto/crypto_utils.dart

Index: sdk/lib/crypto/crypto_utils.dart
diff --git a/sdk/lib/crypto/crypto_utils.dart b/sdk/lib/crypto/crypto_utils.dart
index 32096f155faeb139b6aff7424498baf5349d477b..466ec4590b292cdf622f13a3acec72a343f011fb 100644
--- a/sdk/lib/crypto/crypto_utils.dart
+++ b/sdk/lib/crypto/crypto_utils.dart
@@ -9,10 +9,10 @@ class _LineWrappingStringBuffer {
 
   void add(String s) {
     if (_lineLength != null && _currentLineLength == _lineLength) {
-      _sb.add('\r\n');
+      _sb.write('\r\n');
       _currentLineLength = 0;
     }
-    _sb.add(s);
+    _sb.write(s);
     _currentLineLength++;
   }
 
@@ -27,7 +27,7 @@ abstract class _CryptoUtils {
   static String bytesToHex(List<int> bytes) {
     var result = new StringBuffer();
     for (var part in bytes) {
-      result.add('${part < 16 ? '0' : ''}${part.toRadixString(16)}');
+      result.write('${part < 16 ? '0' : ''}${part.toRadixString(16)}');
     }
     return result.toString();
   }