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/primitives/blockchain/src/error.rs

@@ -69,7 +69,7 @@ pub enum Error {
 	ExtrinsicRootInvalid { received: String, expected: String },
 
 	// `inner` cannot be made member, since it lacks `std::error::Error` trait bounds.
-	#[error("Execution failed: {0:?}")]
+	#[error("Execution failed: {0}")]
 	Execution(Box<dyn sp_state_machine::Error>),
 
 	#[error("Blockchain")]