[clang] [CIR][NFC] Fix an unused variable warning (PR #138110)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-x86_64-debian` running on `lldb-x86_64-debian` while building `clang` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/162/builds/21423

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

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: lang/c/step-target/TestStepTarget.py (192 of 2882)
PASS: lldb-api :: functionalities/data-formatter/data-formatter-stl/generic/bitset/TestDataFormatterGenericBitset.py (193 of 2882)
PASS: lldb-api :: functionalities/thread/concurrent_events/TestConcurrentManySignals.py (194 of 2882)
PASS: lldb-api :: tools/lldb-server/TestPtyServer.py (195 of 2882)
PASS: lldb-api :: commands/target/stop-hooks/TestStopHookScripted.py (196 of 2882)
PASS: lldb-api :: commands/expression/issue_11588/Test11588.py (197 of 2882)
PASS: lldb-api :: lang/cpp/unicode-literals/TestUnicodeLiterals.py (198 of 2882)
PASS: lldb-api :: functionalities/data-formatter/data-formatter-stl/libstdcpp/iterator/TestDataFormatterStdIterator.py (199 of 2882)
PASS: lldb-api :: tools/lldb-dap/breakpoint/TestDAP_setExceptionBreakpoints.py (200 of 2882)
UNRESOLVED: lldb-api :: tools/lldb-dap/optimized/TestDAP_optimized.py (201 of 2882)
******************** TEST 'lldb-api :: tools/lldb-dap/optimized/TestDAP_optimized.py' FAILED ********************
Script:
--
/usr/bin/python3 /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/./lib --env LLVM_INCLUDE_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/include --env LLVM_TOOLS_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/./bin --arch x86_64 --build-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex --lldb-module-cache-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/lldb --compiler /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/clang --dsymutil /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/dsymutil --make /usr/bin/gmake --llvm-tools-dir /home/worker/2.0.1/lldb-x86_64-debian/build/./bin --lldb-obj-root /home/worker/2.0.1/lldb-x86_64-debian/build/tools/lldb --lldb-libs-dir /home/worker/2.0.1/lldb-x86_64-debian/build/./lib -t /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/tools/lldb-dap/optimized -p TestDAP_optimized.py
--
Exit Code: 1

Command Output (stdout):
--
lldb version 21.0.0git (https://github.com/llvm/llvm-project.git revision a9ccb246178a454abba8fb53499012d586e5eea9)
  clang revision a9ccb246178a454abba8fb53499012d586e5eea9
  llvm revision a9ccb246178a454abba8fb53499012d586e5eea9
Skipping the following test categories: ['libc++', 'dsym', 'gmodules', 'debugserver', 'objc']

--
Command Output (stderr):
--
Change dir to: /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/tools/lldb-dap/optimized
runCmd: settings clear --all

output: 

runCmd: settings set symbols.enable-external-lookup false

output: 

runCmd: settings set target.inherit-tcc true

output: 

runCmd: settings set target.disable-aslr false

output: 

runCmd: settings set target.detach-on-error false

output: 

runCmd: settings set target.auto-apply-fixits false

```

</details>

https://github.com/llvm/llvm-project/pull/138110