Revert "Use ProcedureKind.Operator for operators."

pkg/front_end/test/fasta/testing.json

 {
 "":"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.md file.",
   "packages": "../../../../.packages",
   "suites": [
     {
       "name": "scanner",
       "kind": "Chain",
       "source": "scanner/scanner_suite.dart",
@@ skipping 103 matching lines @@
       "../../lib/src/fasta/dill",
       "../../lib/src/fasta/kernel",
       "../../lib/src/fasta/parser",
       "../../lib/src/fasta/parser/bin",
       "../../lib/src/fasta/scanner",
       "../../lib/src/fasta/scanner/bin",
       "../../lib/src/fasta/scanner/testing",
       "../../lib/src/fasta/source",
       "../../lib/src/fasta/testing",
       "../../lib/src/fasta/util",
+      "../../../compiler/lib/src/dart2js.dart",
+      "../../../compiler/tool",
       "dart2js_test.dart",
       "parser/parser_suite.dart",
       "scanner/scanner_suite.dart",
       "compile_test.dart",
       "dart2js_test.dart",
       "kompile_test.dart",
       "outline_test.dart",
       "sdk_test.dart"
     ],
     "exclude": [
       "/third_party/pkg/",
       "/pkg/analyzer/"
     ]
   }
 }