[clang] [WinEH] Fix crash, object unwinding in the except block (PR #172287)

[via cfe-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 51645 tests passed
* 889 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.CodeGen/windows-seh-EHa-TryInFinally.cpp</summary>

```
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\clang.exe -cc1 -internal-isystem C:\_work\llvm-project\llvm-project\build\lib\clang\22\include -nostdsysteminc -triple x86_64-windows -fasync-exceptions -fcxx-exceptions -fexceptions -fms-extensions -x c++ -Wno-implicit-function-declaration -emit-llvm C:\_work\llvm-project\llvm-project\clang\test\CodeGen\windows-seh-EHa-TryInFinally.cpp -o - | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\clang\test\CodeGen\windows-seh-EHa-TryInFinally.cpp
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -cc1 -internal-isystem 'C:\_work\llvm-project\llvm-project\build\lib\clang\22\include' -nostdsysteminc -triple x86_64-windows -fasync-exceptions -fcxx-exceptions -fexceptions -fms-extensions -x c++ -Wno-implicit-function-declaration -emit-llvm 'C:\_work\llvm-project\llvm-project\clang\test\CodeGen\windows-seh-EHa-TryInFinally.cpp' -o -
# .---command stderr------------
# | C:\_work\llvm-project\llvm-project\clang\test\CodeGen\windows-seh-EHa-TryInFinally.cpp:19:5: error: expected '__except' or '__finally' block
# |    19 | int main() {
# |       |     ^
# | 1 error generated.
# `-----------------------------
# error: command failed with exit status: 1
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' 'C:\_work\llvm-project\llvm-project\clang\test\CodeGen\windows-seh-EHa-TryInFinally.cpp'
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\clang\test\CodeGen\windows-seh-EHa-TryInFinally.cpp
# `-----------------------------
# error: command failed with exit status: 2

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/172287