[third-party] Silence warning on benchmark when building with Clang ToT

fixes:
```
[7409/7446] Building CXX object third-party\benchmark\src\CMakeFiles\benchmark.dir\benchmark.cc.obj
C:\git\llvm-project\third-party\benchmark\src\benchmark.cc(172,17): warning: offset of on non-standard-layout type 'State' [-Winvalid-offsetof]
  172 |   static_assert(offsetof(State, error_occurred_) <=
      |                 ^               ~~~~~~~~~~~~~~~
C:\git\llvm_package_18.0.0\build64_stage0\lib\clang\18\include\__stddef_offsetof.h(11,24): note: expanded from macro 'offsetof'
   11 | #define offsetof(t, d) __builtin_offsetof(t, d)
      |                        ^                     ~
1 warning generated.
```