no_std support for substrate trie (#2146)

* no_std trie compile in test_runtime (require to set nightly feature due
to the way hashbrown currently works).

* No nightly with hashmap_core.

* using crate elastic-array

* switch to publish trie crates

* fix default array decl

* bump impl_version for ci

* set all semver when possible wasm, and remove redundant code.

* Actually test use_trie function

* impl version +1

* Bump impl version

substrate/core/trie/src/error.rs

@@ -6,7 +6,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[cfg(feature="std")]
 use std::fmt;
+#[cfg(feature="std")]
 use std::error::Error as StdError;
 
 #[derive(Debug, PartialEq, Eq, Clone)]
@@ -16,12 +18,14 @@ pub enum Error {
 	BadFormat,
 }
 
+#[cfg(feature="std")]
 impl StdError for Error {
 	fn description(&self) -> &str {
 		"codec error"
 	}
 }
 
+#[cfg(feature="std")]
 impl fmt::Display for Error {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		fmt::Debug::fmt(&self, f)