Ruby » Ruby master

debug.rb: Fix debug listing

• lib/debug.rb (script_lines): get source lines from SCRIPT_LINES__ or
  read from the file.
• lib/debug.rb (display_list): use script_lines instead of recursion.
  [Bug #8318]
• lib/debug.rb (line_at): use script_lines same as display_list.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40452 b2dd03c8-39d4-4d8f-98ff-823fe69b080e