[clang] [ast-matcher] Fixed a crash when traverse lambda expr with invalid captures (PR #108689)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `openmp-offload-libc-amdgpu-runtime` running on `omp-vega20-1` while building `clang` at step 10 "Add check check-offload".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/73/builds/5646

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

```
Step 10 (Add check check-offload) failure: 1200 seconds without output running [b'ninja', b'-j 32', b'check-offload'], attempting to kill
...
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/test_libc.cpp (869 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug47654.cpp (870 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug49779.cpp (871 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/wtime.c (872 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug50022.cpp (873 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu :: offloading/bug49021.cpp (874 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu :: offloading/std_complex_arithmetic.cpp (875 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/complex_reduction.cpp (876 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug49021.cpp (877 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/std_complex_arithmetic.cpp (878 of 879)
command timed out: 1200 seconds without output running [b'ninja', b'-j 32', b'check-offload'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1235.786813

```

</details>

https://github.com/llvm/llvm-project/pull/108689