Unicode escape sequence
-----
<?php

"\u{0}";
"\u{114}";
"\u{1F602}";
-----
!!php7
array(
    0: Scalar_String(
        value: @@{"\0"}@@
    )
    1: Scalar_String(
        value: Ĕ
    )
    2: Scalar_String(
        value: @@{"\xF0\x9F\x98\x82"}@@
    )
)
