Subpart9 for async drop (major3) - elaborate_drops changes

Author: azhogin

Cargo.lock

@@ -4099,6 +4099,7 @@ dependencies = [
 name = "rustc_mir_dataflow"
 version = "0.0.0"
 dependencies = [
+ "itertools",
  "polonius-engine",
  "regex",
  "rustc_ast",

compiler/rustc_mir_dataflow/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 # tidy-alphabetical-start
+itertools = "0.12"
 polonius-engine = "0.13.0"
 regex = "1"
 rustc_ast = { path = "../rustc_ast" }