code: function(breakable, label) {
  			this.breakContext = {
  				upper: this.breakContext,
  				breakable: breakable,
  				label: label,
  				brokenForkContext: ForkContext.newEmpty(this.forkContext)
  			};
  			return this.breakContext;
  		}
docs: -------------------------------------------------------------------------- Control Statements -------------------------------------------------------------------------- 
  Creates new context for BreakStatement.
  
  @param {boolean} breakable - The flag to indicate it can break by
  an unlabeled BreakStatement.
  @param {string|null} label - The label of this context.
  @returns {object} The new context.