Remove factory body in *.fromEnvironment, and implement this same behavior

pkg/compiler/lib/src/kernel/elements.dart

Index: pkg/compiler/lib/src/kernel/elements.dart
diff --git a/pkg/compiler/lib/src/kernel/elements.dart b/pkg/compiler/lib/src/kernel/elements.dart
index 305c41a10f1dc1655c7112e4135fc450f39aafc1..8989f5ee92f218c3a038603cc84b43feb4749398 100644
--- a/pkg/compiler/lib/src/kernel/elements.dart
+++ b/pkg/compiler/lib/src/kernel/elements.dart
@@ -120,6 +120,9 @@ abstract class KConstructor extends KFunction implements ConstructorEntity {
   @override
   bool get isTopLevel => false;
 
+  @override
+  bool get isFromEnvironmentConstructor => false;
+
   String get _kind => 'constructor';
 }
 
@@ -137,8 +140,12 @@ class KGenerativeConstructor extends KConstructor {
 }
 
 class KFactoryConstructor extends KConstructor {
+  @override
+  final bool isFromEnvironmentConstructor;
+
   KFactoryConstructor(int memberIndex, KClass enclosingClass, Name name,
-      ParameterStructure parameterStructure, {bool isExternal, bool isConst})
+      ParameterStructure parameterStructure,
+      {bool isExternal, bool isConst, this.isFromEnvironmentConstructor})
       : super(memberIndex, enclosingClass, name, parameterStructure,
             isExternal: isExternal, isConst: isConst);