Make SimulationState accept sdk.Int as value for InitialStake.

[V-Staykov]

Summary

Currently SimulationState accepts int64 as value for InitialStake. This leads to limit in the initial stake. It is later converted to sdk.Int anyways, so it would be better for it to accept sdk.Int and make it possible to set higher values.

Problem Definition

We've added a limit in the minimum self delegation in our fork, so we had to change all tests to use higher values for valdiator creations. This led to TestAppSimulationAfterImport and others like it failing. We needed to change the SimulationState to set higher InitialStakes.

Proposal

Refactor the sims to use sdk.int

---

For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged
• Contributor assigned/self-assigned

[alexanderbez]

ACK. Thanks for the issue @V-Staykov 🙌

[facundomedica]

I'll pick this one up :) Using the new sdkmath "cosmossdk.io/math" instead of sdk "github.com/cosmos/cosmos-sdk/types" 👌