Fixed SqlifyDate function to not return invalid dates when "m" is used.

https://bugs.webkit.org/show_bug.cgi?id=257546
<rdar://problem/110075621>

Reviewed by Alexey Proskuryakov.

Modified the SqlifyDate function such that when "m" is entered, it converts to month multiplied by 31 days, similar to how it treats "d" where it multiplies the number by 7.

* Websites/bugs.webkit.org/Bugzilla/Search.pm:
(SqlifyDate):

Canonical link: https://commits.webkit.org/264758@main

Websites/bugs.webkit.org/Bugzilla/Search.pm

@@ -2217,7 +2217,20 @@ sub SqlifyDate {
         my ($sec, $min, $hour, $mday, $month, $year, $wday)  = localtime($date);
         if ($sign && $sign eq '+') { $amount = -$amount; }
         $startof = 1 if $amount == 0;
-        if ($unit eq 'w') {                  # convert weeks to days
+# WEBKIT_CHANGES: Fixed invalid date returns on some occasions.
+        if ($unit eq 'm') {
+            $month -= $amount;
+            $year += floor($month/12);
+            $month %= 12;
+            if ($startof) {
+                return sprintf("%4d-%02d-01 00:00:00", $year+1900, $month+1);
+            }
+            else {
+                $amount = 31*$amount;
+                $unit = 'd';
+            }
+        }
+        elseif ($unit eq 'w') {                  # convert weeks to days
             $amount = 7*$amount;
             $amount += $wday if $startof;
             $unit = 'd';
@@ -2239,18 +2252,6 @@ sub SqlifyDate {
                                $year+1900-$amount, $month+1, $mday, $hour, $min, $sec);
             }
         }
-        elsif ($unit eq 'm') {
-            $month -= $amount;
-            $year += floor($month/12);
-            $month %= 12;
-            if ($startof) {
-                return sprintf("%4d-%02d-01 00:00:00", $year+1900, $month+1);
-            }
-            else {
-                return sprintf("%4d-%02d-%02d %02d:%02d:%02d", 
-                               $year+1900, $month+1, $mday, $hour, $min, $sec);
-            }
-        }
         elsif ($unit eq 'h') {
             # Special case for 'beginning of an hour'
             if ($startof) {