fix: fix add same key for taints in node

Created by: harrisonliu5

Signed-off-by: harrisonliu5 harrisonliu_5@163.com

What type of PR is this?

/kind bug

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes ##1637 (closed)

Special notes for reviewers:

Additional documentation, usage docs, etc.:

/assign @leoendless