[close #693] Add test for RangeSplitter (#694)

[ti-srebot]

cherry-pick #694 to release-3.3
You can switch your code base to this Pull Request by using git-extras:

# In client-java repo:
git pr https://github.com/tikv/client-java/pull/698

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/client-java.git pr/698:release-3.3-3e02966ac146

---

Signed-off-by: shiyuhang 1136742008@qq.com

What problem does this PR solve?

Issue Number: close #693
Problem Description: Add test for RangeSplitter

What is changed and how does it work?

Add test for RangeSplitter. reference: https://github.com/pingcap/tispark/blob/release-3.1/tikv-client/src/test/java/com/pingcap/tikv/util/RangeSplitterTest.java

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has methods of interface change
• Has persistent data change
• No code

Check List for Tests

This PR has been tested by at least one of the following methods:

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Possible performance regression, WHY: TBD
• Increased code complexity, WHY: TBD
• Breaking backward compatibility, WHY: TBD
• NO side effects

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation
• Need to be included in the release note
• NO related changes

[ti-srebot]

/run-all-tests

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-3.3@a345184). Click here to learn what that means.
Patch has no changes to coverable lines.

Additional details and impacted files

@@              Coverage Diff               @@
##             release-3.3     #698   +/-   ##
==============================================
  Coverage               ?   38.03%           
  Complexity             ?     1602           
==============================================
  Files                  ?      278           
  Lines                  ?    17386           
  Branches               ?     1978           
==============================================
  Hits                   ?     6612           
  Misses                 ?    10116           
  Partials               ?      658           

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.