frame: GenesisBuild::build allowed in no_std (#14107)

* frame: GenesisBuild::build allowed in no_std

i`GenesisBuild::build` function will be required for no_std in no native
runtime world.

`GenesisBuild::build` macro generated function allows to build the runtime
GenesisConfig assembled from all pallets' GenesisConfigs.

* fixes

* GenesisBuild::build avaiable in no-std

- #[cfg(feature = "std")] is not longer added to GenesisBuild implementation.

* system: hash69 available for no-std

* elections-phragmen: panic message fixed for no_std

* frame::suport: doc updated

* test-runtime: default for GenesisConfig

* frame::test-pallet: serde/std added to std feature deps

* Cargo.toml: deps sorted

* Cargo.lock update

cargo update -p frame-support-test-pallet -p frame-support-test

* frame ui tests: cleanup

---------

Co-authored-by: parity-processbot <>

substrate/frame/support/src/lib.rs

@@ -1522,8 +1522,6 @@ pub mod tests {
 
 /// Prelude to be used alongside pallet macro, for ease of use.
 pub mod pallet_prelude {
-	#[cfg(feature = "std")]
-	pub use crate::traits::GenesisBuild;
 	pub use crate::{
 		dispatch::{
 			DispatchClass, DispatchError, DispatchResult, DispatchResultWithPostInfo, Parameter,
@@ -1540,8 +1538,8 @@ pub mod pallet_prelude {
 			},
 		},
 		traits::{
-			ConstU32, EnsureOrigin, Get, GetDefault, GetStorageVersion, Hooks, IsType,
-			PalletInfoAccess, StorageInfoTrait, StorageVersion, TypedGet,
+			ConstU32, EnsureOrigin, GenesisBuild, Get, GetDefault, GetStorageVersion, Hooks,
+			IsType, PalletInfoAccess, StorageInfoTrait, StorageVersion, TypedGet,
 		},
 		Blake2_128, Blake2_128Concat, Blake2_256, CloneNoBound, DebugNoBound, EqNoBound, Identity,
 		PartialEqNoBound, RuntimeDebug, RuntimeDebugNoBound, Twox128, Twox256, Twox64Concat,