Core sdk upgrade to 2.3.4

pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: async
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.8.2"
+    version: "2.9.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -21,21 +21,14 @@ packages:
       name: characters
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.2.0"
-  charcode:
-    dependency: transitive
-    description:
-      name: charcode
-      url: "https://pub.flutter-io.cn"
-    source: hosted
-    version: "1.3.1"
+    version: "1.2.1"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.0"
+    version: "1.1.1"
   collection:
     dependency: transitive
     description:
@@ -49,7 +42,7 @@ packages:
       name: fake_async
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.3.0"
+    version: "1.3.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -66,28 +59,28 @@ packages:
       name: matcher
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.12.11"
+    version: "0.12.12"
   material_color_utilities:
     dependency: transitive
     description:
       name: material_color_utilities
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.1.4"
+    version: "0.1.5"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.7.0"
+    version: "1.8.0"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.8.1"
+    version: "1.8.2"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -99,7 +92,7 @@ packages:
       name: source_span
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.8.2"
+    version: "1.9.0"
   stack_trace:
     dependency: transitive
     description:
@@ -120,21 +113,21 @@ packages:
       name: string_scanner
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.0"
+    version: "1.1.1"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.2.0"
+    version: "1.2.1"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.4.9"
+    version: "0.4.12"
   vector_math:
     dependency: transitive
     description: