Fix multi-sort

[Naruto-kyun]

this.data is change, then this.initBody() load this.options.data, so reorder this.options.data instead

Bug fix?
yes

New Feature?
no

Resolve an issue?
Fix #4616

Example(s)?
Do manual asc on both columns
Before: https://live.bootstrap-table.com/code/wenzhixin/853
After: https://live.bootstrap-table.com/code/Naruto-kyun/5802

[UtechtDustin]

Sure that would fix this problem, but it would create new issues.
With youre change the original data would be sorted!

We have to find a other way to solve that, but thanks for the try :-)

[wenzhixin]

@UtechtDustin is right, for example, use the sortReset option will show the problem: https://live.bootstrap-table.com/code/wenzhixin/5832.