Add test for strength from Japanese nabe

Author: youkidearitai

ext/intl/tests/grapheme_levenshtein.phpt

@@ -58,6 +58,14 @@ $nabe = '邊';
 $nabe_E0100 = "邊󠄀";
 var_dump(grapheme_levenshtein($nabe, $nabe_E0100));
 
+// variable $nabe and $nabe_E0101 is different because that is IVS.
+// $nabe_E0101 is variable selector in U+908A U+E0101.
+// grapheme_levenshtein can catches different only match strength is Collator::IDENTICAL.
+// So result is maybe 1.
+$nabe = '邊';
+$nabe_E0101 = "\u{908A}\u{E0101}";
+var_dump(grapheme_levenshtein($nabe, $nabe_E0101, strength: Collator::IDENTICAL));
+
 // combining character
 var_dump(grapheme_levenshtein("\u{0065}\u{0301}", "\u{00e9}"));
 
@@ -122,6 +130,7 @@ int(2)
 --- Variable selector ---
 int(1)
 int(0)
+int(1)
 int(0)
 --- Corner case ---
 grapheme_levenshtein(): Argument #3 ($insertion_cost) must be greater than 0 and less than or equal to %d