[ruby/date] Extracted common leading pattern

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

ext/date/date_parse.c

@@ -652,8 +652,10 @@ 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*)?"
@@ -662,14 +664,15 @@ parse_time(VALUE str, VALUE hash)
 #endif
 		       ")?"
 		     "|"
-		     "\\d+\\s*h(?:\\s*\\d+m?(?:\\s*\\d+s?)?)?"
+		       "h(?:\\s*\\d+m?(?:\\s*\\d+s?)?)?"
 		     ")"
 		     "(?:"
 		       "\\s*"
 		       "[ap](?:m\\b|\\.m\\.)"
 		     ")?"
 		   "|"
-		   "\\d+\\s*[ap](?:m\\b|\\.m\\.)"
+		     "[ap](?:m\\b|\\.m\\.)"
+		   ")"
 		 ")"
 		 "(?:"
 		   "\\s*"