CI: on host: force 64 bit mode like `make -j2 CI` implicitly does (#7513)
CI: on host: force 64 bit mode like `make -j2 CI` implicitly does (#7513)

It allows to run CI tests on computers having gcc-multilib installed
esp8266/Arduino,esp8266/Arduino,esp8266/Arduino,sticilface/Arduino,esp8266/Arduino,esp8266/Arduino,sticilface/Arduino,sticilface/Arduino,sticilface/Arduino,sticilface/Arduino