tests/fortran/9 cpp: It's okay to link ICL and ifort

This test currently assumes that the fortran compiler is gfotran, and
if we're not using g++ it skips. This patch changes it to skip if the
fotran compiler and the c++ compiler aren't the same family. This still
may skip in some cases it shouldn't (clang and gfort probably work fine
on windows), but it does enable ifort + ICL. Which is hte point.

test cases/fortran/9 cpp/meson.build

@@ -7,7 +7,7 @@ if cpp.get_id() == 'clang'
   error('MESON_SKIP_TEST Clang C++ does not find -lgfortran for some reason.')
 endif
 
-if build_machine.system() == 'windows' and cpp.get_id() != 'gnu'
+if build_machine.system() == 'windows' and cpp.get_id() != fc.get_id()
   error('MESON_SKIP_TEST mixing gfortran with non-GNU C++ does not work.')
 endif