Remove unsafe uses of TypeImpl.withNullability (use TypeSystem instead).

Change-Id: I5df47ca582aa5583055d3700668de992676bc42a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/103541
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>

https://dart.googlesource.com/sdk/+/22c086fbe56102e304197c1d52fbd92d0efcb1f0
diff --git a/commits.json b/commits.json
index 35968b5..b64030c 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "external/github.com/flutter/engine":"ee6a9c40492e54a0ae160293900d9e3b42b725d7",
   "external/github.com/flutter/flutter":"1bd85dd6c207d69c148b92ec8f68244c00dec503",
-  "sdk":"aa785d938b209c8c409d4a9a11340d6ac926fa51"
+  "sdk":"22c086fbe56102e304197c1d52fbd92d0efcb1f0"
 }
\ No newline at end of file