Add a new host function for reporting fatal errors; make WASM backtraces readable when printing out errors (#10741)

* Add a new host function for reporting fatal errors

* Fix one of the wasmtime executor tests

* Have `#[runtime_interface(wasm_only)]` actually mean WASM-only, and not no_std-only

* Print out errors through `Display` instead of `Debug`

* Switch one more trait to require `Error` for its error instead of only `Debug`

* Align to review comments

substrate/client/beefy/src/worker.rs

@@ -378,7 +378,7 @@ where
 							.expect("forwards closure result; the closure always returns Ok; qed.");
 					}
 				}) {
-					error!(target: "beefy", "🥩 Failed to get hash for block number {}; err: {:?}",
+					error!(target: "beefy", "🥩 Failed to get hash for block number {}: {}",
 						block_num, err);
 				}