test_unicode_normalize.rb: skip if not found

* test/test_unicode_normalize.rb (read_tests): do nothing if the
  test data file is not found.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48387 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/test_unicode_normalize.rb

@@ -21,6 +21,8 @@ class TestUnicodeNormalize < Test::Unit::TestCase
         code_string.split(/\s/).collect { |cp| cp.to_i(16) }.pack('U*')
       end + [line[1]+1])
     end
+  rescue Errno::ENOENT => e
+    skip e.message
   end
 
   def to_codepoints(string)