Move sp-npos-elections-solution-type to frame-election-provider-support (#11016)

* Move `sp-npos-elections-solution-type`
to `frame-election-provider-support`
First stab at it, will need to amend some more stuff

* Fixing tests

* Fixing tests

* Fixing cargo.toml for std configuration

* fmt

* Committing suggested changes
renaming, and re exporting macro.

* Removing unneeded imports

substrate/primitives/npos-elections/fuzzer/src/compact.rs

@@ -1,38 +0,0 @@
-use honggfuzz::fuzz;
-use sp_npos_elections::{generate_solution_type, sp_arithmetic::Percent};
-use sp_runtime::codec::{Encode, Error};
-
-fn main() {
-	generate_solution_type!(#[compact] pub struct InnerTestSolutionCompact::<
-		VoterIndex = u32,
-		TargetIndex = u32,
-		Accuracy = Percent,
-	>(16));
-	loop {
-		fuzz!(|fuzzer_data: &[u8]| {
-			let result_decoded: Result<InnerTestSolutionCompact, Error> =
-				<InnerTestSolutionCompact as codec::Decode>::decode(&mut &*fuzzer_data);
-			// Ignore errors as not every random sequence of bytes can be decoded as
-			// InnerTestSolutionCompact
-			if let Ok(decoded) = result_decoded {
-				// Decoding works, let's re-encode it and compare results.
-				let reencoded: std::vec::Vec<u8> = decoded.encode();
-				// The reencoded value may or may not be equal to the original fuzzer output.
-				// However, the original decoder should be optimal (in the sense that there is no
-				// shorter encoding of the same object). So let's see if the fuzzer can find
-				// something shorter:
-				if fuzzer_data.len() < reencoded.len() {
-					panic!("fuzzer_data.len() < reencoded.len()");
-				}
-				// The reencoded value should definitely be decodable (if unwrap() fails that is a
-				// valid panic/finding for the fuzzer):
-				let decoded2: InnerTestSolutionCompact =
-					<InnerTestSolutionCompact as codec::Decode>::decode(&mut reencoded.as_slice())
-						.unwrap();
-				// And it should be equal to the original decoded object (resulting from directly
-				// decoding fuzzer_data):
-				assert_eq!(decoded, decoded2);
-			}
-		});
-	}
-}