Simplify Tty methods.

Library/Homebrew/utils/tty.rb

@@ -63,27 +63,22 @@ def show_cursor
 
  sig { returns(T.nilable([Integer, Integer])) }
  def size
- `/bin/stty size 2>/dev/null`.presence&.split&.map(&:to_i)
+ return @size if defined?(@size)
+
+ height, width = `/bin/stty size 2>/dev/null`.presence&.split&.map(&:to_i)
+ return if height.nil? || width.nil?
+
+ @size = [height, width]
  end
 
  sig { returns(Integer) }
  def height
- @height ||= begin
- height, = size
- height, = `/usr/bin/tput lines 2>/dev/null`.split if height.zero?
- height ||= 40
- height.to_i
- end
+ @height ||= size&.first || `/usr/bin/tput lines 2>/dev/null`.presence&.to_i || 40
  end
 
  sig { returns(Integer) }
  def width
- @width ||= begin
- _, width = size
- width, = `/usr/bin/tput cols 2>/dev/null`.split if width.zero?
- width ||= 80
- width.to_i
- end
+ @width ||= size&.second || `/usr/bin/tput cols 2>/dev/null`.presence&.to_i || 80
  end
 
  sig { params(string: String).returns(String) }