sp-std removal from substrate/primitives (#3274)

This PR removes sp-std crate from substrate/primitives sub-directories.

For now crates that have `pub use` of sp-std or export macros that would
necessitate users of the macros to `extern crate alloc` have been
excluded from this PR.

There should be no breaking changes in this PR.

---------

Co-authored-by: Koute <koute@users.noreply.github.com>

substrate/primitives/tracing/Cargo.toml

@@ -21,7 +21,6 @@ features = ["with-tracing"]
 targets = ["wasm32-unknown-unknown", "x86_64-unknown-linux-gnu"]
 
 [dependencies]
-sp-std = { path = "../std", default-features = false }
 codec = { version = "3.6.1", package = "parity-scale-codec", default-features = false, features = [
 	"derive",
 ] }
@@ -36,7 +35,6 @@ default = ["std"]
 with-tracing = ["codec/derive", "codec/full"]
 std = [
 	"codec/std",
-	"sp-std/std",
 	"tracing-core/std",
 	"tracing-subscriber",
 	"tracing/std",

substrate/primitives/tracing/src/lib.rs

@@ -37,6 +37,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+extern crate alloc;
+
 #[cfg(feature = "std")]
 use tracing;
 pub use tracing::{

substrate/primitives/tracing/src/types.rs

@@ -15,11 +15,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use alloc::{vec, vec::Vec};
 use codec::{Decode, Encode};
 /// Types for wasm based tracing. Loosly inspired by `tracing-core` but
 /// optimised for the specific use case.
 use core::{fmt::Debug, format_args};
-use sp_std::{vec, vec::Vec, Writer};
 
 /// The Tracing Level – the user can filter by this
 #[derive(Clone, Encode, Decode, Debug)]
@@ -132,9 +132,9 @@ impl From<bool> for WasmValue {
 
 impl From<core::fmt::Arguments<'_>> for WasmValue {
 	fn from(inp: core::fmt::Arguments<'_>) -> WasmValue {
-		let mut buf = Writer::default();
+		let mut buf = alloc::string::String::default();
 		core::fmt::write(&mut buf, inp).expect("Writing of arguments doesn't fail");
-		WasmValue::Formatted(buf.into_inner())
+		WasmValue::Formatted(buf.into_bytes())
 	}
 }