std::jule::integrated: fix the U16PtrToStr function ignores null-term…

…ination which is causes segfault

std/jule/integrated/conv.jule

@@ -56,10 +56,10 @@ unsafe fn U16PtrToStr(s: *u16): str {
     let mut i = 0
     for ; i++ {
         let r = s[i]
+        codePage = append(codePage, r)
         if r == 0 {
             ret str(utf16::Decode(codePage))
         }
-        codePage = append(codePage, r)
     }
     ret ""
 }