[clang] [clang] allow fetch_{min, max} for atomic pointer types (PR #182699)

[via cfe-commits]

github-actions[bot] wrote:

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

* 52665 tests passed
* 970 tests skipped
* 1 test failed

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

### Clang
<details>
<summary>Clang.Sema/atomic-ops.c</summary>

```
Exit Code: 1

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\23\include -nostdsysteminc C:\_work\llvm-project\llvm-project\clang\test\Sema\atomic-ops.c -verify=expected,fp80,noi128 -fgnuc-version=4.2.1 -ffreestanding    -Wno-default-const-init-unsafe -fsyntax-only -triple=i686-linux-gnu -std=c11
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -cc1 -internal-isystem 'C:\_work\llvm-project\llvm-project\build\lib\clang\23\include' -nostdsysteminc 'C:\_work\llvm-project\llvm-project\clang\test\Sema\atomic-ops.c' -verify=expected,fp80,noi128 -fgnuc-version=4.2.1 -ffreestanding -Wno-default-const-init-unsafe -fsyntax-only -triple=i686-linux-gnu -std=c11
# .---command stderr------------
# | error: diagnostics with 'error' severity expected but not seen: 
# |   File C:\_work\llvm-project\llvm-project\clang\test\Sema\atomic-ops.c Line 232 'fp80-error': must be a pointer to atomic integer or supported floating point type
# |   File C:\_work\llvm-project\llvm-project\clang\test\Sema\atomic-ops.c Line 238 'fp80-error': must be a pointer to atomic integer or supported floating point type
# | error: diagnostics with 'error' severity seen but not expected: 
# |   File C:\_work\llvm-project\llvm-project\clang\test\Sema\atomic-ops.c Line 232: address argument to atomic operation must be a pointer to atomic integer, pointer or supported floating point type ('_Atomic(long double) *' invalid)
# |   File C:\_work\llvm-project\llvm-project\clang\test\Sema\atomic-ops.c Line 238: address argument to atomic operation must be a pointer to atomic integer, pointer or supported floating point type ('_Atomic(long double) *' invalid)
# | 4 errors generated.
# `-----------------------------
# error: command failed with exit status: 1

--

```
</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/182699