Fix a target method of a test

* test/ruby/test_string.rb (test_delete): I guess
  this line should be a test case which asserts
  coderange is handled correctly when a result of
  String#delete has non-ASCII characters.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60354 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_string.rb

@@ -673,7 +673,7 @@ CODE
     assert_equal("a".hash, "a\u0101".delete("\u0101").hash, '[ruby-talk:329267]')
     assert_equal(true, "a\u0101".delete("\u0101").ascii_only?)
     assert_equal(true, "a\u3041".delete("\u3041").ascii_only?)
-    assert_equal(false, "a\u3041\u3042".tr("\u3041", "a").ascii_only?)
+    assert_equal(false, "a\u3041\u3042".delete("\u3041").ascii_only?)
 
     assert_equal("a", "abc\u{3042 3044 3046}".delete("^a"))
     assert_equal("bc\u{3042 3044 3046}", "abc\u{3042 3044 3046}".delete("a"))