[ruby/date] Extracted common leading pattern

https://github.com/ruby/date/commit/ec86dbbdc1

ext/date/date_parse.c

@@ -652,24 +652,27 @@ parse_time(VALUE str, VALUE hash)
 {
     static const char pat_source[] =
 		"("
+		   "\\d+\\s*"
 		   "(?:"
-		     "\\d+\\s*:\\s*\\d+"
 		     "(?:"
+		       ":\\s*\\d+"
+		       "(?:"
 #ifndef TIGHT_PARSER
-		       "\\s*:\\s*\\d+(?:[,.]\\d*)?"
+		         "\\s*:\\s*\\d+(?:[,.]\\d*)?"
 #else
-		       "\\s*:\\s*\\d+(?:[,.]\\d+)?"
+		         "\\s*:\\s*\\d+(?:[,.]\\d+)?"
 #endif
+		       ")?"
+		     "|"
+		       "h(?:\\s*\\d+m?(?:\\s*\\d+s?)?)?"
+		     ")"
+		     "(?:"
+		       "\\s*"
+		       "[ap](?:m\\b|\\.m\\.)"
 		     ")?"
 		   "|"
-		     "\\d+\\s*h(?:\\s*\\d+m?(?:\\s*\\d+s?)?)?"
-		   ")"
-		   "(?:"
-		     "\\s*"
 		     "[ap](?:m\\b|\\.m\\.)"
-		   ")?"
-		 "|"
-		   "\\d+\\s*[ap](?:m\\b|\\.m\\.)"
+		   ")"
 		 ")"
 		 "(?:"
 		   "\\s*"