utf8.h: Add UNICODE_IS_NONCHAR_GIVEN_NOT_SUPER

If we already know the input is a Unicode code point, we can save a
conditional in checking if it is a Unicode non-character code point.

Author: khwilliamson

regexec.c

@@ -11658,7 +11658,7 @@ Perl_is_grapheme(pTHX_ const U8 * strbeg, const U8 * s, const U8 * strend, const
     PERL_ARGS_ASSERT_IS_GRAPHEME;
 
     if (   UNLIKELY(UNICODE_IS_SUPER(cp))
-        || UNLIKELY(UNICODE_IS_NONCHAR(cp)))
+        || UNLIKELY(UNICODE_IS_NONCHAR_GIVEN_NOT_SUPER(cp)))
     {
         /* These are considered graphemes */
         return true;

utf8.c

@@ -1952,7 +1952,7 @@ Perl_utf8_to_uv_msgs_helper_(const U8 * const s0,
                     possible_problems |= UTF8_GOT_SUPER;
                 }
             }
-            else if (UNLIKELY(UNICODE_IS_NONCHAR(uv))) {
+            else if (UNLIKELY(UNICODE_IS_NONCHAR_GIVEN_NOT_SUPER(uv))) {
                 if (flags & (UTF8_DISALLOW_NONCHAR|UTF8_WARN_NONCHAR)) {
                     possible_problems |= UTF8_GOT_NONCHAR;
                 }

utf8.h

@@ -1112,11 +1112,13 @@ non-character code points
  * the Unicode legal max */
 #define UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv)                    \
                                   UNLIKELY(((UV) (uv) & 0xFFFE) == 0xFFFE)
+#define UNICODE_IS_NONCHAR_GIVEN_NOT_SUPER(uv)                              \
+    (   UNLIKELY(UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv))                     \
+     || UNLIKELY(UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv)))
 
 #define UNICODE_IS_NONCHAR(uv)                                              \
-    (       UNLIKELY(UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv))                 \
-     || (   UNLIKELY(UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv))      \
-         && LIKELY(! UNICODE_IS_SUPER(uv))))
+                       (   LIKELY(! UNICODE_IS_SUPER(uv))                   \
+                        && UNLIKELY(UNICODE_IS_NONCHAR_GIVEN_NOT_SUPER(uv)))
 
 /*
 =for apidoc Am|bool|UTF8_IS_NONCHAR|const U8 *s|const U8 *e