sp-runtime: make parity-util-mem dependency optional (#12657)

* `sp-runtime`: make `parity-util-mem` dependency optional

* Use default-features = false for sp-runtime in sp-keyring

* Remove parity-util-mem from sp-core

* Cargo.lock

* Restore default-features for keyring dependency

substrate/Cargo.lock

@@ -9525,7 +9525,6 @@ dependencies = [
  "merlin",
  "num-traits",
  "parity-scale-codec",
- "parity-util-mem",
  "parking_lot 0.12.1",
  "primitive-types",
  "rand 0.7.3",

substrate/primitives/core/Cargo.toml

@@ -40,7 +40,6 @@ sp-std = { version = "4.0.0", default-features = false, path = "../std" }
 sp-debug-derive = { version = "4.0.0", default-features = false, path = "../debug-derive" }
 sp-storage = { version = "6.0.0", default-features = false, path = "../storage" }
 sp-externalities = { version = "0.12.0", optional = true, path = "../externalities" }
-parity-util-mem = { version = "0.12.0", default-features = false, features = ["primitive-types"] }
 futures = { version = "0.3.21", optional = true }
 dyn-clonable = { version = "0.9.0", optional = true }
 thiserror = { version = "1.0.30", optional = true }
@@ -78,7 +77,6 @@ bench = false
 [features]
 default = ["std"]
 std = [
-	"parity-util-mem/std",
 	"merlin?/std",
 	"full_crypto",
 	"log/std",

substrate/primitives/runtime/Cargo.toml

@@ -19,7 +19,7 @@ either = { version = "1.5", default-features = false }
 hash256-std-hasher = { version = "0.15.2", default-features = false }
 impl-trait-for-tuples = "0.2.2"
 log = { version = "0.4.17", default-features = false }
-parity-util-mem = { version = "0.12.0", default-features = false, features = ["primitive-types"] }
+parity-util-mem = { version = "0.12.0", default-features = false, features = ["primitive-types"], optional = true }
 paste = "1.0"
 rand = { version = "0.7.2", optional = true }
 scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }

substrate/primitives/runtime/src/transaction_validity.rs

@@ -226,9 +226,8 @@ impl From<UnknownTransaction> for TransactionValidity {
 /// Depending on the source we might apply different validation schemes.
 /// For instance we can disallow specific kinds of transactions if they were not produced
 /// by our local node (for instance off-chain workers).
-#[derive(
-	Copy, Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug, parity_util_mem::MallocSizeOf,
-)]
+#[derive(Copy, Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(parity_util_mem::MallocSizeOf))]
 pub enum TransactionSource {
 	/// Transaction is already included in block.
 	///