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/offchain/src/lib.rs

@@ -194,7 +194,7 @@ where
 				if let Err(e) = run {
 					tracing::error!(
 						target: LOG_TARGET,
-						"Error running offchain workers at {:?}: {:?}",
+						"Error running offchain workers at {:?}: {}",
 						at,
 						e
 					);