Fix contracts integration test

[ascjones]

Prior to paritytech/substrate#12383, setting proof_size to 0 worked for all extrinsics. Following that a proper value needed to be supplied. However u64::MAX was too high as it breached the limit for normal class transactions weight (I think about 0.75 * MAX_BLOCK_WEIGHT).

Interestingly 0 still worked for instantiate_with_code and call, but the fix was to set it to u64::MAX / 2.

[lexnv]

I was trying the same thing, then decided to adjust the ref_time to fit the contract:

1_250_000_000_000 out of gas

1_280_000_000_000 out of gas

1_290_000_000_000 out of gas

1_295_000_000_000 out of gas

1_299_000_000_000 block limit

1_300_000_000_000 block limit

1_310_000_000_000 block limit

1_375_000_000_000 block limit

But couldn't find any appropriate values that would accept our dummy contract, which is strange.

I also waited for 2 blocks between the instantiate_with_code call and instantiate without any effect, based on the comment from substrate about exhausted transactions: Invalidity might also be temporary. In case of ExhaustsResources the transaction does not fit to the current block, but it might be okay for the next one.

[ascjones]

The issue appears to have been introduced in paritytech/substrate#12383

[lexnv]

Replicating the test using the old API resulted in the same behavior:

        use crate::node_runtime::runtime_types::sp_weights::OldWeight;

        let instantiate_tx = node_runtime::tx().contracts().instantiate_old_weight(
            100_000_000_000_000_000, // endowment
            OldWeight(
                1_295_000_000_000,
            ), // gas_limit
            None,                    // storage_deposit_limit
            code_hash,
            data,
            salt,
        );

[lexnv]

Thanks for fixing this! LGTM!