[llvm-windres] Pass user preprocessor arguments before the input filename (#75389)

If passing the windres option --preprocessor, the default arguments "-E
-xc -DRC_INVOKED" aren't passed. If these are passed explicitly by the
user via --preprocessor-arg instead, we need to make sure that "-xc" is
passed before the input filename, as this compiler/preprocessor option
only has an effect on input files that follow it.

This fixes one of the issues with llvm-windres observed in
https://github.com/msys2/MINGW-packages/pull/19157.