Add file test/ruby/enc/test_grapheme_breaks.rb to test String#each_grapheme_cluster
and \X extended grapheme cluster matcher in regular expressions against test data
provided by Unicode (ucd/auxiliary/GraphemeBreakTest.txt).
Some lines in the data file are ignored, as follows:
- Lines with a surrogate, because Ruby doesn't handle these
- The case of "\r\n", because there is a bug (#15337) in the implementation
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65955 b2dd03c8-39d4-4d8f-98ff-823fe69b080e