Merge branch '3.4' into 4.3

* 3.4:
  Fix inconsistent return points.
  [Security/Core] UserInterface::getPassword() can return null
  [Router] Fix TraceableUrlMatcher behaviour with trailing slash

Author: nicolas-grekas

Parser/Tokenizer/TokenizerEscaping.php

@@ -58,6 +58,8 @@ private function replaceUnicodeSequences(string $value): string
             if (0x10000 > $c) {
                 return \chr(0xE0 | $c >> 12).\chr(0x80 | $c >> 6 & 0x3F).\chr(0x80 | $c & 0x3F);
             }
+
+            return '';
         }, $value);
     }
 }