Fix deprecation warnings in analyzer and analysis server.

pkg/analyzer/bin/formatter.dart

Index: pkg/analyzer/bin/formatter.dart
diff --git a/pkg/analyzer/bin/formatter.dart b/pkg/analyzer/bin/formatter.dart
index c4c689eeb9ff13fbece5d1675c5586fc0599e3f1..28436f6670c250628ed7ded9eacf74fe8031615d 100755
--- a/pkg/analyzer/bin/formatter.dart
+++ b/pkg/analyzer/bin/formatter.dart
@@ -227,7 +227,7 @@ _printUsage() {
         ..write('\n\n')
         ..write('Usage: $BINARY_NAME [flags] [path...]\n\n')
         ..write('Supported flags are:\n')
-        ..write('${argParser.getUsage()}\n\n');
+        ..write('${argParser.usage}\n\n');
   _log(buffer.toString());
 }