Cherry-picks for 1.9.1 (#40005)

dart-lang/sdk@1ef83b8 Upgrade to tflite_native@0.2.2 by Ari Aye
dart-lang/sdk@e9bad9b Upgrade tflite_native to v0.2.1 for silent tflite dynamic library by Ari Aye
dart-lang/sdk@7c7d369 Check for null tokens while walking backward from cursor by lambdabaa
diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index 36e6307..4463910 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-cc88fa45dbf4c55bc23cecea17fb90f43bccf588
+b863200c37df4ed378042de11c4e9ff34e4e58c9