function enterFunction(node) {
			scopeInfo = {
				isBound: isCalleeOfBindMethod(node),
				thisFound: false,
				upper: scopeInfo,
			};
		}
Adds a scope information object to the stack.
@param {ASTNode} node A node to add. This node is a FunctionExpression
     or a FunctionDeclaration node.
@returns {void}