Runtime: fix caml_utf8_of_utf16 bug in high surrogate case

Author: hhugo

CHANGES.md

@@ -51,6 +51,7 @@
 * Runtime: fix Int64.of_string overflow check (#1874)
 * Runtime: fix caml_string_concat when not using JS strings (#1874)
 * Runtime: consistent bigarray hashing across all architectures (#1977)
+* Runtime: fix caml_utf8_of_utf16 bug in high surrogate case (#2008)
 * Tools: fix jsoo_mktop and jsoo_mkcmis (#1877)
 * Toplevel: fix for when use-js-strings is disabled (#1997)
 

runtime/js/mlBytes.js

@@ -104,7 +104,7 @@ function caml_utf8_of_utf16(s) {
         0x80 | (c & 0x3f),
       );
     } else if (
-      c >= 0xdbff ||
+      c > 0xdbff ||
       i + 1 === l ||
       (d = s.charCodeAt(i + 1)) < 0xdc00 ||
       d > 0xdfff