(VIDEO-AT-LINK)Billionaire presidential hopeful says it’s a protest against immigration.When you’re Donald Trump, another rescinded corporate partnership is nothing if not an opportunity to galvanize your supposedly growing base of political supporters. The billionaire real estate mogul, reality-television personality, and Republican presidential hopeful has spent the past week taking Twitter pot-shots at Macy’s after the department store chain severed ties with Trump and his line of menswear amid the uproar over Trump’s recent derogatory comments about Mexican immigrants. On Monday, Trump — who, last week, gleefully pointed out on Twitter when Macy’s stock had fallen by less than 0.5% — tweeted...