debug.rb: Fix debug listing

* lib/debug.rb (display_list): Fix debug listing when called from the
  same file it has been required.  patch by Dario Bertini <berdario AT
  gmail.com> [Bug #8318] [fix GH-280]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40450 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-04-25

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40451 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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
tracer.rb: File.readlines

* lib/tracer.rb (get_line): simply read by File.readlines.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40453 b2dd03c8-39d4-4d8f-98ff-823fe69b080e