More analyzer updates, and handle negative_tests

test/codegen/expect/collection/src/unmodifiable_wrappers.txt

Index: test/codegen/expect/collection/src/unmodifiable_wrappers.txt
diff --git a/test/codegen/expect/collection/src/unmodifiable_wrappers.txt b/test/codegen/expect/collection/src/unmodifiable_wrappers.txt
index 8a7e83828fb27875edd085400901619eb107e43a..b559b3e95fc9d0cf8396750095951e7a8ea4e302 100644
--- a/test/codegen/expect/collection/src/unmodifiable_wrappers.txt
+++ b/test/codegen/expect/collection/src/unmodifiable_wrappers.txt
@@ -1,7 +1,7 @@
 // Messages from compiling unmodifiable_wrappers.dart
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand', 'Iterable.fold' and 'Iterable.map' (package:collection/src/unmodifiable_wrappers.dart, line 20, col 7)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand', 'Iterable.fold' and 'Iterable.map' (package:collection/src/unmodifiable_wrappers.dart, line 93, col 7)
-warning: [DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to E (package:collection/src/unmodifiable_wrappers.dart, line 59, col 28)
-warning: [DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to E (package:collection/src/unmodifiable_wrappers.dart, line 63, col 21)
-warning: [DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to V (package:collection/src/unmodifiable_wrappers.dart, line 151, col 41)
-warning: [DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to V (package:collection/src/unmodifiable_wrappers.dart, line 159, col 27)
+severe: [NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_THREE] Missing concrete implementation of 'Iterable.expand', 'Iterable.fold' and 'Iterable.map' (package:collection/src/unmodifiable_wrappers.dart, line 20, col 7)
+severe: [NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_THREE] Missing concrete implementation of 'Iterable.expand', 'Iterable.fold' and 'Iterable.map' (package:collection/src/unmodifiable_wrappers.dart, line 93, col 7)
+warning: [STRONG_MODE_DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to E (package:collection/src/unmodifiable_wrappers.dart, line 59, col 28)
+warning: [STRONG_MODE_DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to E (package:collection/src/unmodifiable_wrappers.dart, line 63, col 21)
+warning: [STRONG_MODE_DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to V (package:collection/src/unmodifiable_wrappers.dart, line 151, col 41)
+warning: [STRONG_MODE_DOWN_CAST_COMPOSITE] Unsound implicit cast from dynamic to V (package:collection/src/unmodifiable_wrappers.dart, line 159, col 27)