If need_exe_wrapper() is called while figuring out the language compiler,
the MachineInfo isn't complete yet, so machine_info_can_run() would return
False despite not cross compiling.

Make sure this fails loudly.

Squash of the following cherry-picked commits:
- mesonbuild@df833b0
- mesonbuild@c108d5b
- mesonbuild@eba9e7e