cleanup patch generation to preseve comments and remove @patch

test/generated_sdk/lib/core/bool.dart

Index: test/generated_sdk/lib/core/bool.dart
diff --git a/test/generated_sdk/lib/core/bool.dart b/test/generated_sdk/lib/core/bool.dart
index 36cd96b89bac22b864095cbef56204764df02218..14bc535875437edccd1c76b40ee5d94213ccc827 100644
--- a/test/generated_sdk/lib/core/bool.dart
+++ b/test/generated_sdk/lib/core/bool.dart
@@ -12,7 +12,24 @@ part of dart.core;
  * bool.
  */
 class bool {
-  @patch
+  /**
+   * Returns the boolean value of the environment declaration [name].
+   *
+   * The boolean value of the declaration is `true` if the declared value is
+   * the string `"true"`, and `false` if the value is `"false"`.
+   *
+   * In all other cases, including when there is no declaration for `name`,
+   * the result is the [defaultValue].
+   *
+   * Example:
+   *
+   *     const loggingFlag = const bool.fromEnvironment("logging");
+   *
+   * If you want to use a different truth-string, you can use the
+   * [String.fromEnvironment] constructor directly:
+   *
+   *     const isLoggingOn = (const String.fromEnvironment("logging") == "on");
+   */
   factory bool.fromEnvironment(String name, {bool defaultValue: false}) {
     throw new UnsupportedError(
         'bool.fromEnvironment can only be used as a const constructor');