Issue 48124. Set enclosingElement for synthetic FieldElementImpl in top-merge.

Bug: https://github.com/dart-lang/sdk/issues/48124
Change-Id: I0ad7cfe46edd4333fe292c7ddbe1b0044335ec0a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/228723
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

https://dart.googlesource.com/sdk/+/b449fe4398f5188a54694bfcea8f2dc8f645e45e
diff --git a/commits.json b/commits.json
index 641efa8..cff4168 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "external/github.com/flutter/engine":"31b1a1d05803ec9fa25ae0f7b2b0f078ff3980b1",
   "external/github.com/flutter/flutter":"3c0f3f4ee18e457cd7d4376fc19499d2ae66ca5b",
-  "sdk":"df2e8fedbbe23e5a79dbda114c2ff3c115ac85a1"
+  "sdk":"b449fe4398f5188a54694bfcea8f2dc8f645e45e"
 }
\ No newline at end of file