bugfix: fix Byte[] type to ensure the correct primary key value.

[maple525866]

• I have read the CONTRIBUTING.md guidelines.
• I have registered the PR changes.

Ⅰ. Describe what this PR did

When the primary key is of type BINARY(16), pkVal is actually a byte[] array.

• For a byte[] array, StringBuilder.append(Object obj) calls obj.toString().

• The default toString() method of byte[] returns a string representing the memory address of the Java object.

• This address string is stored in the pk field of the global lock table lock_table.

The problem lies in the undo_log serialization logic: it correctly serializes the contents of the byte[] array, not the memory address.

My solution: Based on the buildLockKey, I performed special processing on the byte[] type. Calling ArrayUtils.toString(pkVal) returns the actual content instead of the memory address.

In addition, I added corresponding unit tests to verify the correctness of the modification.

Ⅱ. Does this pull request fix one issue?

fixes #7738

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

mvn clean test

Ⅴ. Special notes for reviews

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.61%. Comparing base (6f1e37d) to head (c3cbc58).
⚠️ Report is 1 commits behind head on 2.x.

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x    #7761      +/-   ##
============================================
- Coverage     67.62%   67.61%   -0.01%     
- Complexity      992      994       +2     
============================================
  Files          1323     1323              
  Lines         50155    50157       +2     
  Branches       5928     5929       +1     
============================================
- Hits          33915    33912       -3     
- Misses        13316    13317       +1     
- Partials       2924     2928       +4     

Files with missing lines	Coverage Δ
.../rm/datasource/exec/BaseTransactionalExecutor.java	75.11% <100.00%> (+0.23%)	⬆️

... and 7 files with indirect coverage changes

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[slievrly]

LGTM