message: remove set_balance from test_api as a duplicate fn
diff: @@ -175,19 +175,6 @@ where
  })
  }
  -/// Sets the balance of `account_id` to `new_balance`.
  -pub fn set_balance<T>(account_id: T::AccountId, new_balance: T::Balance)
  -where
  - T: Environment<Balance = u128>, // Just temporary for the MVP!
  - <T as Environment>::AccountId: From<[u8; 32]>,
  -{
  - <EnvInstance as OnInstance>::on_instance(|instance| {
  - instance
  - .engine
  - .set_balance(scale::Encode::encode(&account_id), new_balance);
  - })
  -}
  -
  /// Sets the value transferred from the caller to the callee as part of the call.
  ///
  /// Please note that the acting accounts should be set with [`set_caller()`] and [`set_callee()`] beforehand.
  