S_unexpected_non_continuation_text: Move ARGS_ASSERT

to the top of the function.  It was only further down because we were on
C89.

Author: khwilliamson

utf8.c

@@ -956,6 +956,8 @@ S_unexpected_non_continuation_text(pTHX_ const U8 * const s,
                                          /* How many bytes should there be? */
                                          const STRLEN expect_len)
 {
+    PERL_ARGS_ASSERT_UNEXPECTED_NON_CONTINUATION_TEXT;
+
     /* Return the malformation warning text for an unexpected continuation
      * byte. */
 
@@ -966,8 +968,6 @@ S_unexpected_non_continuation_text(pTHX_ const U8 * const s,
     const U8 * x = s + non_cont_byte_pos;
     const U8 * e = s + print_len;
 
-    PERL_ARGS_ASSERT_UNEXPECTED_NON_CONTINUATION_TEXT;
-
     /* We don't need to pass this parameter, but since it has already been
      * calculated, it's likely faster to pass it; verify under DEBUGGING */
     assert(expect_len == UTF8SKIP(s));