[clang] [clang][Sema] Optimize ~SemaDiagnosticBuilder (PR #142252)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `publish-sphinx-docs` running on `as-worker-4` while building `clang` at step 10 "Publish docs-lldb-html".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/45/builds/12825

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 10 (Publish docs-lldb-html) failure: 'rsync -vrl ...' (failure)
kex_exchange_identification: Connection closed by remote host
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(235) [sender=3.1.3]
Step 11 (Publish docs-flang-html) failure: 'rsync -vrl ...' (failure)
kex_exchange_identification: Connection closed by remote host
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(235) [sender=3.1.3]
Step 12 (Publish docs-openmp-html) failure: 'rsync -vrl ...' (failure)
kex_exchange_identification: Connection closed by remote host
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(235) [sender=3.1.3]
Step 13 (Publish docs-polly-html) failure: 'rsync -vrl ...' (failure)
kex_exchange_identification: Connection closed by remote host
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(235) [sender=3.1.3]

```

</details>

https://github.com/llvm/llvm-project/pull/142252