Use null-aware operators to clean up the code

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

Index: pkg/analyzer/lib/src/generated/engine.dart
diff --git a/pkg/analyzer/lib/src/generated/engine.dart b/pkg/analyzer/lib/src/generated/engine.dart
index 96333ad7d93e0c0c7f3b0b23225932e7d5dccc85..8db8ee0c418e92cb41211998939eed66d53ffbbb 100644
--- a/pkg/analyzer/lib/src/generated/engine.dart
+++ b/pkg/analyzer/lib/src/generated/engine.dart
@@ -816,7 +816,7 @@ class AnalysisEngine {
    * analysis engine to the given [logger].
    */
   void set logger(Logger logger) {
-    this._logger = logger == null ? Logger.NULL : logger;
+    this._logger = logger ?? Logger.NULL;
   }
 
   /**
@@ -1200,14 +1200,6 @@ class AnalysisOptionsImpl implements AnalysisOptions {
   bool enableAsync = true;
 
   /**
-   * A flag indicating whether interface libraries are to be supported (DEP 40).
-   */
-  bool get enableConditionalDirectives => true;
-
-  @deprecated
-  void set enableConditionalDirectives(_) {}
-
-  /**
    * A flag indicating whether generic methods are to be supported (DEP 22).
    */
   bool enableGenericMethods = false;
@@ -1349,6 +1341,14 @@ class AnalysisOptionsImpl implements AnalysisOptions {
     _analyzeFunctionBodiesPredicate = value;
   }
 
+  /**
+   * A flag indicating whether interface libraries are to be supported (DEP 40).
+   */
+  bool get enableConditionalDirectives => true;
+
+  @deprecated
+  void set enableConditionalDirectives(_) {}
+
   @override
   int encodeCrossContextOptions() =>
       (enableAssertMessage ? ENABLE_ASSERT_FLAG : 0) |