change diaeresis from above to below for better visibility

In test/ruby/test_regexp.rb and test/ruby/test_string.rb, change
some instances of COMBINING DIAERESIS (U+0308, above) to
COMBINING DIAERESIS BELOW (U+0324) to make it more easily visible
in test output, particularly in the context of double quotes
surrounding strings.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66192 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_regexp.rb

@@ -955,8 +955,8 @@ class TestRegexp < Test::Unit::TestCase
     assert_match /\A\X\z/, "\u{600 20}"
     assert_match /\A\X\z/, "\u{261d 1F3FB}"
     assert_match /\A\X\z/, "\u{1f600}"
-    assert_match /\A\X\z/, "\u{20 308}"
-    assert_match /\A\X\X\z/, "\u{a 308}"
+    assert_match /\A\X\z/, "\u{20 324}"
+    assert_match /\A\X\X\z/, "\u{a 324}"
     assert_match /\A\X\X\z/, "\u{d 308}"
     assert_match /\A\X\z/, "\u{1F477 1F3FF 200D 2640 FE0F}"
     assert_match /\A\X\z/, "\u{1F468 200D 1F393}"

test/ruby/test_string.rb

@@ -991,8 +991,8 @@ CODE
     end
 
     [
-      ["\u{a 308}", ["\u000A", "\u0308"]],
-      ["\u{d 308}", ["\u000D", "\u0308"]],
+      ["\u{a 324}", ["\u000A", "\u0324"]],
+      ["\u{d 324}", ["\u000D", "\u0324"]],
       ["abc", ["a", "b", "c"]],
     ].each do |str, grapheme_clusters|
       assert_equal grapheme_clusters, str.each_grapheme_cluster.to_a
@@ -1023,8 +1023,8 @@ CODE
       assert_predicate g.dup.taint.grapheme_clusters[0], :tainted?
     end
 
-    assert_equal ["\u000A", "\u0308"], "\u{a 308}".grapheme_clusters
-    assert_equal ["\u000D", "\u0308"], "\u{d 308}".grapheme_clusters
+    assert_equal ["\u000A", "\u0324"], "\u{a 324}".grapheme_clusters
+    assert_equal ["\u000D", "\u0324"], "\u{d 324}".grapheme_clusters
     assert_equal ["a", "b", "c"], "abc".b.grapheme_clusters
 
     if ENUMERATOR_WANTARRAY