Ninja: Revert "Exclude NVHPC -Werror flags during Fortran preprocessing"

Revert commit 6b58cdd4cf (Ninja: Exclude NVHPC -Werror flags during
Fortran preprocessing, 2023-04-04).  Since commit 9d40f01442 (NVHPC: Use
-Werror for COMPILE_OPTIONS_WARNING_AS_ERROR, 2023-04-13), `nvfortran`
can handle the plain `-Werror` flag during preprocessing.

Issue: #24665
2 files changed