Move all main methods to tool/.

pkg/front_end/lib/src/fasta/bin/log_analyzer.dart

-// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import 'dart:convert' show JSON;
-
-import 'dart:io';
-
-import 'package:testing/src/run_tests.dart' show CommandLine;
-
-main(List<String> arguments) async {
-  CommandLine cl = CommandLine.parse(arguments);
-  Set<String> fields = cl.commaSeparated("--fields=");
-  if (fields.isEmpty) {
-    fields.addAll(["uri", "offset", "json:error"]);
-  }
-  for (String filename in cl.arguments) {
-    String json = await new File(filename).readAsString();
-    Map<String, dynamic> data = JSON.decode(json) as Map<String, dynamic>;
-    StringBuffer sb = new StringBuffer();
-    bool isFirst = true;
-    for (String field in fields) {
-      if (!isFirst) {
-        sb.write(":");
-      }
-      if (field.startsWith("json:")) {
-        field = field.substring(5);
-        sb.write(JSON.encode(data[field]));
-      } else {
-        sb.write(data[field]);
-      }
-      isFirst = false;
-    }
-    print("$sb");
-  }
-}