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GH-35611: [C++] Remove unnecessary safe operations for ListBuilder and BinaryBuilder (#35613)



### Rationale for this change

There are several safety checks/operations that can be optimized to enhance performance of ListBuilder and BinaryBuild

### What changes are included in this PR?

1. Remove redundant safety checks
2. replace Append with UnsafeAppend when possible
3. In AppendArraySlice, pre-allocate space for the whole batch.

### Are these changes tested?

Yes, by existing tests in array_test.cc.

### Are there any user-facing changes?

No. 

* Closes: #35611

Authored-by: Jin Shang <shangjin1997@gmail.com>
Signed-off-by: Antoine Pitrou <antoine@python.org>