fix: tab can't scroll to the right position

[Sociosarbis]

Please makes sure the items are checked before submitting your PR, thank you!

• Rebase before creating a PR to keep commit history clear.

• Only One commit

• No eslint errors

• 原来的代码会出现不能选中的tab滚动到container的中间位置的问题。

• 先假设在进行最后一次滚动前依然没有到达目标位置，距离设为delta，那么最后一次会只是滚动delta / 15，不能让delta归零。

[codecov-io]

Codecov Report

Merging #3649 into v2 will decrease coverage by 0.1%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##               v2    #3649      +/-   ##
==========================================
- Coverage   18.89%   18.79%   -0.11%     
==========================================
  Files         226      226              
  Lines        5598     5598              
  Branches      725      725              
==========================================
- Hits         1058     1052       -6     
- Misses       4422     4428       +6     
  Partials      118      118

Impacted Files	Coverage Δ
src/components/tab/tab.vue	0% <0%> (ø)	⬆️
src/components/inline-calendar/util.js	69.41% <0%> (-3.53%)	⬇️
src/components/picker/index.vue	5.37% <0%> (-2.16%)	⬇️
src/components/inline-calendar/index.vue	28.76% <0%> (-0.69%)	⬇️

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[Sociosarbis]

• src/components/inline-calendar/util.js
• src/components/picker/index.vue
• src/components/inline-calendar/index.vue
  这个三个文件都没做更改，却没通过codecov的测试。