Add test case for surrogate pair

Author: youkidearitai

ext/mbstring/tests/mb_trim.phpt

@@ -48,6 +48,11 @@ var_dump(mb_rtrim("ああああああああああああああああああああ
 echo "== default params ==\n";
 var_dump(mb_trim(" \f\n\r\v\x00\u{00A0}\u{1680}\u{2000}\u{2001}\u{2002}\u{2003}\u{2004}\u{2005}\u{2006}\u{2007}\u{2008}\u{2009}\u{200A}\u{2028}\u{2029}\u{202F}\u{205F}\u{3000}\u{0085}\u{180E}"));
 
+echo "== Surrogate pair ==\n";
+var_dump(mb_ltrim("\u{FFFE}漢字", "\u{FFFE}\u{FEFF}"));
+var_dump(bin2hex(mb_ltrim(mb_convert_encoding("\u{FFFE}漢字", "UTF-16LE", "UTF-8"), mb_convert_encoding("\u{FFFE}\u{FEFF}", "UTF-16LE", "UTF-8"), "UTF-16LE")));
+var_dump(bin2hex(mb_ltrim(mb_convert_encoding("\u{FEFF}漢字", "UTF-16BE", "UTF-8"), mb_convert_encoding("\u{FFFE}\u{FEFF}", "UTF-16BE", "UTF-8"), "UTF-16BE")));
+
 echo "== SJIS ==\n";
 var_dump(mb_convert_encoding(mb_trim("\x81\x40\x82\xa0\x81\x40", "\x81\x40", "SJIS"), "UTF-8", "SJIS"));
 
@@ -96,6 +101,10 @@ string(15) "いああああ"
 string(102) "あああああああああああああああああああああああああああああああああい"
 == default params ==
 string(0) ""
+== Surrogate pair ==
+string(6) "漢字"
+string(8) "226f575b"
+string(8) "6f225b57"
 == SJIS ==
 string(3) "あ"
 == $encoding throws ValueError ==