Fix tests for Rust 1.65

[alvicsam]

In order to update rust version in CI image tests should be fixed:
This PR contains ci image with updated rust and can be used for fixing them.

error: non-binding let on a synchronization lock
  --> node/core/runtime-api/src/tests.rs:92:8
   |
92 |             let _ = self.availability_cores_wait.lock().unwrap();
   |                 ^   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this binding will immediately drop the value assigned to it
   |                 |
   |                 this lock is not assigned to a binding and is immediately dropped
   |
   = note: `#[deny(let_underscore_lock)]` on by default
help: consider binding to an unused variable to avoid immediately dropping the value
   |
92 |             let _unused = self.availability_cores_wait.lock().unwrap();
   |                 ~~~~~~~
help: consider immediately dropping the value
   |
92 |             drop(self.availability_cores_wait.lock().unwrap());
   |             ~~~~~                                            +
error: could not compile `polkadot-node-core-runtime-api` due to previous error

cc https://github.com/paritytech/ci_cd/issues/653