GH-48311: [C++] Fix OOB memory access in buffered IO

[chegoryu]

Rationale for this change

Fixing: #48311

What changes are included in this PR?

Applied fix from #48311 and added test

Are these changes tested?

Yes, added test, without my patch test fails with debug check:

Note: Google Test filter = TestBufferedInputStream.PeekAfterExhaustingBuffer
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from TestBufferedInputStream
[ RUN      ] TestBufferedInputStream.PeekAfterExhaustingBuffer
/Users/chegoryu/Junk/git/arrow/cpp/src/arrow/io/buffered.cc:337:  Check failed: buffer_->size() - buffer_pos_ >= nbytes

Are there any user-facing changes?

No, this PR fixes a bug

• GitHub Issue: [C++] OOB write in buffered IO #48311

[github-actions]

⚠️ GitHub issue #48311 has been automatically assigned in GitHub to PR creator.

[chegoryu]

@wgtmac Hi, I don't know who to ping, so I chose you since you’ve looked at one of my reviews.

Can you suggest the right person to call to review this? This bug is really annoying and appears very randomly (and looks like a corrupted allocator, so it's hard to debug).

[wgtmac]

cc @mapleFU

[mapleFU]

Can you rewrite comment in SetBufferSize? Since buffer_pos_ would be rewritten now

[chegoryu]

Missed that comment, thanks, fixed