It wrongly used all linenos of ISeq#trace_points which includes not only
line events but also call, return, and other events.  So, the result
included some linenos that can not be covered at all by line coverage.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66468 b2dd03c8-39d4-4d8f-98ff-823fe69b080e