Upgradable contracts using set_code function (#10690)

* poc logic

* set_code_hash impl, tests, benchmark

* Address @xgreenx's comments

* Move func defs closer to set_storage

* Check if code exists

- increment/decrement codehash refcount

* Document error for non-existing code hash

* Revert unrelated change

* Changes due to @athei's review

* Fix error handling

- comment errors: ReturnCodes
- update mock ext implementation
- return Error::CodeNotFound when no code for such hash

* Emit ContractCodeUpdated when setting new code_hash

* Address @athei's comments

* Move related defs to the bottom

* Minor comment update

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* Improve docs

* Improve docs

* Update frame/contracts/src/wasm/runtime.rs

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* Refactor set_code_hash test

* Minor change to benchmark

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* Minor change to benchmark

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* Minor comment refactor

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* Address @HCastano's comments

* Update seal_set_code_hash comment

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Move set_code_hash after delegate_call

* Move function to the bottom

* Moved and changed banchmark, added verify block

* Bring back previous benchmark

* Remove skip_meta for seal_set_code_hash

* Bring back skip_meta for seal_set_storage_per_new_kb

* Apply weights

Co-authored-by: Alexander Theißen <alex.theissen@me.com>
Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

substrate/frame/contracts/src/benchmarking/mod.rs

@@ -1971,6 +1971,46 @@ benchmarks! {
 		let origin = RawOrigin::Signed(instance.caller.clone());
 	}: call(origin, instance.addr, 0u32.into(), Weight::MAX, None, vec![])
 
+	seal_set_code_hash {
+		let r in 0 .. API_BENCHMARK_BATCHES;
+		let code_hashes = (0..r * API_BENCHMARK_BATCH_SIZE)
+			.map(|i| {
+				let new_code = WasmModule::<T>::dummy_with_bytes(i);
+				Contracts::<T>::store_code_raw(new_code.code, whitelisted_caller())?;
+				Ok(new_code.hash)
+			})
+			.collect::<Result<Vec<_>, &'static str>>()?;
+		let code_hash_len = code_hashes.get(0).map(|x| x.encode().len()).unwrap_or(0);
+		let code_hashes_bytes = code_hashes.iter().flat_map(|x| x.encode()).collect::<Vec<_>>();
+		let code_hashes_len = code_hashes_bytes.len();
+
+		let code = WasmModule::<T>::from(ModuleDefinition {
+			memory: Some(ImportedMemory::max::<T>()),
+			imported_functions: vec![ImportedFunction {
+				module: "__unstable__",
+				name: "seal_set_code_hash",
+				params: vec![
+					ValueType::I32,
+				],
+				return_type: Some(ValueType::I32),
+			}],
+			data_segments: vec![
+				DataSegment {
+					offset: 0,
+					value: code_hashes_bytes,
+				},
+			],
+			call_body: Some(body::repeated_dyn(r * API_BENCHMARK_BATCH_SIZE, vec![
+				Counter(0, code_hash_len as u32), // code_hash_ptr
+				Regular(Instruction::Call(0)),
+				Regular(Instruction::Drop),
+			])),
+			.. Default::default()
+		});
+		let instance = Contract::<T>::new(code, vec![])?;
+		let origin = RawOrigin::Signed(instance.caller.clone());
+	}: call(origin, instance.addr, 0u32.into(), Weight::MAX, None, vec![])
+
 	// We make the assumption that pushing a constant and dropping a value takes roughly
 	// the same amount of time. We follow that `t.load` and `drop` both have the weight
 	// of this benchmark / 2. We need to make this assumption because there is no way