Revert "Reduce use of getClosureInfoForMember and cleanup closure_test"

pkg/compiler/lib/src/js_model/closure.dart

 // Copyright (c) 2017, 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 file.
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
 import '../common/tasks.dart';
 import '../constants/expressions.dart';
@@ skipping 147 matching lines @@
   @override
   ScopeInfo getScopeInfo(MemberEntity entity) {
     // TODO(johnniwinther): Remove this check when constructor bodies a created
     // eagerly with the J-model; a constructor body should have it's own
     // [ClosureRepresentationInfo].
     if (entity is ConstructorBodyEntity) {
       ConstructorBodyEntity constructorBody = entity;
       entity = constructorBody.constructor;
     }
 
-    ScopeInfo scopeInfo = _scopeMap[entity];
-    assert(
-        scopeInfo != null, failedAt(entity, "Missing scope info for $entity."));
-    return scopeInfo;
+    return _scopeMap[entity] ?? getClosureInfoForMember(entity);
   }
 
   // TODO(efortuna): Eventually capturedScopesMap[node] should always
   // be non-null, and we should just test that with an assert.
   @override
   CapturedScope getCapturedScope(MemberEntity entity) {
     MemberDefinition definition = _elementMap.getMemberDefinition(entity);
     switch (definition.kind) {
       case MemberKind.regular:
       case MemberKind.constructor:
@@ skipping 23 matching lines @@
 
   @override
   ClosureRepresentationInfo getClosureInfo(ir.Node node) {
     var closure = _localClosureRepresentationMap[node];
     assert(
         closure != null,
         "Corresponding closure class not found for $node. "
         "Closures found for ${_localClosureRepresentationMap.keys}");
     return closure;
   }
+
+  @override
+  ClosureRepresentationInfo getClosureInfoForMemberTesting(
+      MemberEntity entity) {
+    return _memberClosureRepresentationMap[entity];
+  }
+
+  @override
+  ClosureRepresentationInfo getClosureInfoForTesting(ir.Node node) {
+    return _localClosureRepresentationMap[node];
+  }
 }
 
 class KernelScopeInfo {
   final Set<ir.VariableDeclaration> localsUsedInTryOrSync;
   final bool hasThisLocal;
   final Set<ir.VariableDeclaration> boxedVariables;
   // If boxedVariables is empty, this will be null, because no variables will
   // need to be boxed.
   final NodeBox capturedVariablesAccessor;
 
@@ skipping 357 matching lines @@
   KernelScopeInfo scopeInfo;
 
   /// Collected [CapturedScope] data for nodes.
   Map<ir.Node, KernelCapturedScope> capturedScopesMap =
       <ir.Node, KernelCapturedScope>{};
 
   /// Collected [ScopeInfo] data for nodes.
   Map<ir.FunctionNode, KernelScopeInfo> closuresToGenerate =
       <ir.FunctionNode, KernelScopeInfo>{};
 }