seal: Fail instantiate if new contract is below subsistence threshold (#6719)

* seal: Fail instantiate if new contract is below subsistence threshold

We need each contract that exists to be above the subsistence threshold
in order to keep up the guarantuee that we always leave a tombstone behind
with the exception of a contract that called `ext_terminate`.

* Fixup executor test

* Bump runtime

substrate/bin/node/executor/tests/basic.rs

@@ -591,6 +591,8 @@ fn deploying_wasm_contract_should_work() {
 		&charlie(),
 	);
 
+	let subsistence = pallet_contracts::Config::<Runtime>::subsistence_threshold_uncached();
+
 	let b = construct_block(
 		&mut new_test_ext(compact_code_unwrap(), false),
 		1,
@@ -610,7 +612,7 @@ fn deploying_wasm_contract_should_work() {
 				signed: Some((charlie(), signed_extra(1, 0))),
 				function: Call::Contracts(
 					pallet_contracts::Call::instantiate::<Runtime>(
-						1 * DOLLARS,
+						1 * DOLLARS + subsistence,
 						500_000_000,
 						transfer_ch,
 						Vec::new()