Fix for translation of \!= to \!identical(), but use == and \!= for Enum.

pkg/analyzer/lib/src/generated/sdk_io.dart

Index: pkg/analyzer/lib/src/generated/sdk_io.dart
diff --git a/pkg/analyzer/lib/src/generated/sdk_io.dart b/pkg/analyzer/lib/src/generated/sdk_io.dart
index afbf2704db4bddc1eeb36c974f0919bb9ec4d445..eedc729506f5034e2e28eb7d04721e592b226cd1 100644
--- a/pkg/analyzer/lib/src/generated/sdk_io.dart
+++ b/pkg/analyzer/lib/src/generated/sdk_io.dart
@@ -433,7 +433,7 @@ class SdkLibrariesReader {
   /**
    * A flag indicating whether the dart2js path should be used when it is available.
    */
-  bool _useDart2jsPaths = false;
+  final bool _useDart2jsPaths;
 
   /**
    * Initialize a newly created library reader to use the dart2js path if the given value is
@@ -441,9 +441,7 @@ class SdkLibrariesReader {
    *
    * @param useDart2jsPaths `true` if the dart2js path should be used when it is available
    */
-  SdkLibrariesReader(bool useDart2jsPaths) {
-    this._useDart2jsPaths = useDart2jsPaths;
-  }
+  SdkLibrariesReader(this._useDart2jsPaths);
 
   /**
    * Return the library map read from the given source.