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/consensus/manual-seal/src/rpc.rs

@@ -155,7 +155,10 @@ pub fn send_result<T: std::fmt::Debug>(
 ) {
 	if let Some(sender) = sender.take() {
 		if let Err(err) = sender.send(result) {
-			log::warn!("Server is shutting down: {:?}", err)
+			match err {
+				Ok(value) => log::warn!("Server is shutting down: {:?}", value),
+				Err(error) => log::warn!("Server is shutting down with error: {}", error),
+			}
 		}
 	} else {
 		// instant seal doesn't report errors over rpc, simply log them.