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/transaction-pool/api/src/lib.rs

@@ -355,7 +355,7 @@ impl<TPool: LocalTransactionPool> OffchainSubmitTransaction<TPool::Block> for TP
 		result.map(|_| ()).map_err(|e| {
 			log::warn!(
 				target: "txpool",
-				"(offchain call) Error submitting a transaction to the pool: {:?}",
+				"(offchain call) Error submitting a transaction to the pool: {}",
 				e
 			)
 		})