[pallet-revive] do not trap the caller on instantiations with duplicate contracts

[xermicus]

This PR changes the behavior of instantiate when the resulting contract address already exists (because the caller tried to instantiate the same contract with the same salt multiple times): Instead of trapping the caller, return an error code.

Solidity allows catching this, which doesn't work if we are trapping the caller. For example, the change makes the following snippet work:

try new Foo{salt: hex"00"}() returns (Foo) {
    // Instantiation was successful (contract address was free and constructor did not revert)
} catch {
    // This branch is expected to be taken if the instantiation failed because of a duplicate salt
}

revive PR: paritytech/revive#188

[xermicus]

/cmd prdoc --audience runtime_dev --bump major