load data bug

[zoujia-cm]

issue: #22735

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:
When read data from file in client end, a '\n' will be add to the end of the byte array. This amy result to the exception of inserting last fields of the last terms.

What is changed and how it works?

Proposal: xxx

What's Changed:
delete '\n' at the end of the byte array while read data from client file

How it Works:
'\n' make the last field of the last term out of the format. after moving it, the problem can be resolved

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• Need to cherry-pick to the release branch

Check List

Tests

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

Side effects

• Performance regression
  • Consumes more CPU
  • Consumes more MEM
• Breaking backward compatibility

Release note

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

zoujia seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[sre-bot]

No release note, Please follow https://github.com/pingcap/community/blob/master/contributors/release-note-checker.md

[sre-bot]

Please follow PR Title Format:

• pkg [, pkg2, pkg3]: what's changed

Or if the count of mainly changed packages are more than 3, use

• *: what's changed