evm: fixed commented out simulations, pubsub, and handler tests (#655)

* evm: fixed commented out simulations, pubsub, and handler tests

fixes #640

simulations are very basic: they can be built and executed,
but they don't generate any EVM-related transactions yet.
(It should be a matter of adding simulation-related code to the
modules + potentially extra helpers to the simulation.)
handler tests miss some extra assertions due to changes
in the return values snapshotting logic (ADR-001 and ADR-002).

Besides the test suites identified in the audit,
there's also "importer_test.go" which wasn't yet fixed.
(it'd require major rewriting + extra test resources)

* gofumpt

x/evm/simulation/genesis.go

@@ -0,0 +1,27 @@
+package simulation
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/types/module"
+
+	"github.com/tharsis/ethermint/x/evm/types"
+)
+
+// RandomizedGenState generates a random GenesisState for nft
+func RandomizedGenState(simState *module.SimulationState) {
+	params := types.NewParams(types.DefaultEVMDenom, true, true, types.DefaultChainConfig())
+	if simState.Rand.Uint32()%2 == 0 {
+		params = types.NewParams(types.DefaultEVMDenom, true, true, types.DefaultChainConfig(), 1344, 1884, 2200, 2929, 3198, 3529)
+	}
+	evmGenesis := types.NewGenesisState(params, []types.GenesisAccount{})
+
+	bz, err := json.MarshalIndent(evmGenesis, "", " ")
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("Selected randomly generated %s parameters:\n%s\n", types.ModuleName, bz)
+
+	simState.GenState[types.ModuleName] = simState.Cdc.MustMarshalJSON(evmGenesis)
+}