imp(staking): add CreateValidator unit test for precompiled contract staking

[luchenqun]

Description

add CreateValidator unit test for precompiled contract staking, for more details see related #2030

[luchenqun]

I need some time to study your relevant precompile contract test code and then complete the tests.

[codecov]

Codecov Report

Merging #2050 (2527533) into main (6b89f64) will increase coverage by 0.38%.
Report is 1 commits behind head on main.
The diff coverage is n/a.

❗ Current head 2527533 differs from pull request most recent head 8a560f3. Consider uploading reports for the commit 8a560f3 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2050      +/-   ##
==========================================
+ Coverage   70.06%   70.44%   +0.38%     
==========================================
  Files         340      340              
  Lines       25492    25492              
==========================================
+ Hits        17861    17959      +98     
+ Misses       6713     6609     -104     
- Partials      918      924       +6     

Files	Coverage Δ
precompiles/staking/events.go	71.10% <ø> (+7.79%)	⬆️
precompiles/staking/types.go	88.35% <ø> (+13.47%)	⬆️

... and 1 file with indirect coverage changes

[luchenqun]

@fedekunze @Vvaradinov You can start review the code for me now. If there are any missing unit tests or improvements that need to be made, please tell me in the comments.

[MalteHerrmann]

Thanks for the contribution, great work! Left two suggestions for the tests, but looks good 🙏

[CLAassistant]

All committers have signed the CLA.

[0xstepit]

Good job @luchenqun and thanks for your contribution!