Fix for a couple of cascade tests.

pkg/analyzer/test/generated/parser_fasta_test.dart

Index: pkg/analyzer/test/generated/parser_fasta_test.dart
diff --git a/pkg/analyzer/test/generated/parser_fasta_test.dart b/pkg/analyzer/test/generated/parser_fasta_test.dart
index cd5912f7f2d31c2f5b59866c0faecb44fd8cb333..60874b4a64023f454f52b347617a4942aed695dd 100644
--- a/pkg/analyzer/test/generated/parser_fasta_test.dart
+++ b/pkg/analyzer/test/generated/parser_fasta_test.dart
@@ -376,24 +376,12 @@ class ExpressionParserTest_Fasta extends FastaParserTestCase
 
   @override
   @failingTest
-  void test_parseCascadeSection_p_assign_withCascade() {
-    super.test_parseCascadeSection_p_assign_withCascade();
-  }
-
-  @override
-  @failingTest
   void test_parseCascadeSection_p_assign_withCascade_typeArgumentComments() {
     super.test_parseCascadeSection_p_assign_withCascade_typeArgumentComments();
   }
 
   @override
   @failingTest
-  void test_parseCascadeSection_p_assign_withCascade_typeArguments() {
-    super.test_parseCascadeSection_p_assign_withCascade_typeArguments();
-  }
-
-  @override
-  @failingTest
   void test_parseCascadeSection_pa_typeArgumentComments() {
     super.test_parseCascadeSection_pa_typeArgumentComments();
   }
@@ -768,7 +756,7 @@ class FastaParserTestCase extends Object
   @override
   Expression parseCascadeSection(String code) {
     var cascadeExpression = _parseExpression('null$code') as CascadeExpression;
-    return cascadeExpression.cascadeSections.single;
+    return cascadeExpression.cascadeSections.first;
   }
 
   @override