Expand spec files to realpaths

* spec/mspec/lib/mspec/utils/script.rb (MSpecScript#entries): expand
  the given spec path to the realpath, not to require a library by
  realpath and symbolic link path from the spec file.

  reapply r64749 and r64751 overridden by r64830.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64845 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/mspec/lib/mspec/utils/script.rb

@@ -189,7 +189,11 @@ class MSpecScript
     end
 
     patterns.each do |pattern|
-      expanded = File.expand_path(pattern)
+      begin
+        expanded = File.realpath(pattern)
+      rescue Errno::ENOENT
+        next
+      end
       if File.file?(expanded) && expanded.end_with?('.rb')
         return [expanded]
       elsif File.directory?(expanded)