Cherry-picks for 1.9.1 (#12011)

1ef83b8 Upgrade to tflite_native@0.2.2 by Ari Aye
e9bad9b Upgrade tflite_native to v0.2.1 for silent tflite dynamic library by Ari Aye
7c7d369 Check for null tokens while walking backward from cursor by lambdabaa
diff --git a/DEPS b/DEPS
index b44dba0..237ee4e 100644
--- a/DEPS
+++ b/DEPS
@@ -34,7 +34,7 @@
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': '74e4033d316abb6cc2290051ec85534caf4dca54',
+  'dart_revision': '1ef83b86ae637ffe7359173804cbc6d3fa25e6db',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py