Prepare for rust stable 1.60 (#11138)

* Prepare for rust stable 1.59

Besides preparing the UI tests this also adds a new script update-rust-stable.sh script for
simplifying the update of a rust stable version. This script will run all UI tests for the new
rust stable version and updating the expected output.

* Ensure we run the UI tests in CI

* use staging ci image

* More test updates

* Unignore test (#11097)

* empty commit for pipeline rerun

* empty commit for pipeline rerun

* Try to make clippy happy

* More clippy fixes

* FMT

* ci image production

Co-authored-by: alvicsam <alvicsam@gmail.com>
Co-authored-by: Alexander Samusev <41779041+alvicsam@users.noreply.github.com>

substrate/primitives/version/src/embed.rs

@@ -44,8 +44,7 @@ pub fn embed_runtime_version(
 		.apis
 		.iter()
 		.map(Encode::encode)
-		.map(|v| v.into_iter())
-		.flatten()
+		.flat_map(|v| v.into_iter())
 		.collect::<Vec<u8>>();
 
 	module.set_custom_section("runtime_apis", apis);