MADRID—Spain deployed its military to the Moroccan border on Tuesday as thousands of migrants jumped fences or swam onto European soil for the second day in a row after Rabat loosened border controls amid a deepening diplomatic spat. …Morocco’s Foreign Ministry has said Madrid’s move to assist Brahim Ghali, head of the Polisario Front, was “inconsistent with the spirit of partnership and good neighborliness” and vowed there would be “consequences.”