S_parse_ident: Collapse two branches into one

These branches differ only
    1)  in part of the conditions that indicate to take them, so combine
        those conditions together,
    2)  the number of bytes to advance, which is easily determinable

Otherwise they are identical, so it is easier to understand if they are
made common

Author: khwilliamson

toke.c

@@ -10379,32 +10379,24 @@ S_parse_ident(pTHX_ const char *s, const char * const s_end,
             } while (isWORDCHAR_A(*s));
         }
         else if (   allow_package
-                 && *s == '\''
-                 && FEATURE_APOS_AS_NAME_SEP_IS_ENABLED
-                 && isIDFIRST_lazy_if_safe(s + 1, s_end, is_utf8))
-        {   /* Convert the apostrophe to "::" */
-            if (*d >= e - 2) {
-                goto too_long;
-            }
-
-            *(*d)++ = ':';
-            *(*d)++ = ':';
-            s++;
-        }
-        else if (allow_package && *s == ':' && s[1] == ':'
-           /* Disallow things like Foo::$bar. For the curious, this is
-            * the code path that triggers the "Bad name after" warning
-            * when looking for barewords.
-            */
-           && !(check_dollar && s[2] == '$'))
+                 && (   (   *s == '\''
+                         && FEATURE_APOS_AS_NAME_SEP_IS_ENABLED
+                         && isIDFIRST_lazy_if_safe(s+1, s_end, is_utf8))
+                            /* Below we convert the apostrophe to "::" */
+                     || (   *s == ':' && s[1] == ':'
+                            /* Disallow things like Foo::$bar. For the
+                             * curious, this is the code path that triggers
+                             * the "Bad name after" warning when looking for
+                             * barewords. */
+                          && !(check_dollar && s[2] == '$'))))
         {
             if (*d >= e - 2) {
                 goto too_long;
             }
 
             *(*d)++ = ':';
             *(*d)++ = ':';
-            s += 2;
+            s += (*s == ':') ? 2 : 1;
         }
         else    /* None of the above means have come to the end of any
                    identifier*/