So Walmart gives its employees a raise with their big corporate tax cut. Then they are shutting down 63 Sam's Clubs,

The "raises" and bonuses are clearly a public relations stunt.  Walmart has never cared about its employees, only itself.   But if they make themselves look good in the eyes of the public, they stand to make billions in revenue.  If they make people think that they care, they're more likely to shop there (as opposed to online or other companies).  While this sounds good to the store employees, you can be sure that upper management will receive over 10 times that amount in their "bonuses".

Closing down stores is usually a way for a company to "restructure" or gain quick capital.  They shed low profit stores (usually selling the property or not have to pay rent) and ax middle management, thus giving them more "on-hand" capital (although it mak take several months for this to show on their finances).  This makes the overall corporation look healthier which in turn makes their stock worth more (hopefully).  It can cost a company nearly $1 million a day just to open the doors of 1 store (utilities, insurance, taxes, payroll, etc.).  Shuttering stores isn't something a company does overnight (even though that's how it looks from the customer and employee perspective).  It takes many months of planning and a lot of money.