[clang] Fix clang/test/SemaCXX/msvc-pragma-function-no-builtin-attr.cpp for x86 (PR #119986)

[Richard Dzenis via cfe-commits]

RIscRIpt wrote:

I reproduced the problem locally by adding `-m32` flag to `%clang_cl`. Changes in this PR fix the test failure.

https://github.com/llvm/llvm-project/pull/119986