[vm, tfa] Fix tree-shaking of late final fields with initializers

TFA tree shaker removes initializers of fields which cannot be accessed
but retained due to an entry point pragma / dynamic interface.

For late final fields with initializers that changes semantics as
late final fields without initializers have an implicit setter.
Such setter is not accounted in the kernel AST
(Field.setterReference == null and Field.hasSetter == false) and
it doesn't get an assigned selector id, which causes a crash in
dispatch table generator.

The change fixes this bug by retaining initializers for late final
fields. The initializer code is still replaced with
throw "Attempt to execute code removed by Dart AOT compiler (TFA)".

TEST=pkg/vm/testcases/transformations/type_flow/transformer/regress_b404559785.dart

Bug: b/404559785
Change-Id: Id998a715ea75a4768414997ce66bcdd1d4f19189
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/416720
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>

https://dart.googlesource.com/sdk/+/1b6f89d284dc30afc52147158aae6a2ace6ab0c0

DEPS

diff --git a/DEPS b/DEPS
index 7cd4cc3..be0e31a 100644
--- a/DEPS
+++ b/DEPS
@@ -238,7 +238,7 @@
 ]
 
 deps = {
-  'flutter/engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '42bdd6071f5fc09183bf40c779dee211675d3d4a',
+  'flutter/engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '1b6f89d284dc30afc52147158aae6a2ace6ab0c0',
 
   'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + 'bf3826d2ce928dc8ed0d66c0aeb4c8c3a86705ab',
 

commits.json

diff --git a/commits.json b/commits.json
index 989dd6e..54a08c0 100644
--- a/commits.json
+++ b/commits.json
@@ -1,4 +1,4 @@
 {
   "flutter":"bf3826d2ce928dc8ed0d66c0aeb4c8c3a86705ab",
-  "flutter/engine/src/flutter/third_party/dart":"42bdd6071f5fc09183bf40c779dee211675d3d4a"
+  "flutter/engine/src/flutter/third_party/dart":"1b6f89d284dc30afc52147158aae6a2ace6ab0c0"
 }
\ No newline at end of file