Update wording of warning message, and reinstate 'UTC' fallback for ctor

Author: derickr

ext/date/php_date.c

@@ -538,7 +538,7 @@ static char* guess_timezone(const timelib_tzdb *tzdb)
 		}
 
 		if (!timelib_timezone_id_is_valid(DATEG(default_timezone), tzdb)) {
-			php_error_docref(NULL, E_WARNING, "Invalid date.timezone value '%s'", DATEG(default_timezone));
+			php_error_docref(NULL, E_WARNING, "UTC was used as timezone, because the date.timezone value '%s' is invalid", DATEG(default_timezone));
 			return "UTC";
 		}
 

ext/date/tests/bug73239.phpt

@@ -11,4 +11,4 @@ try {
 ?>
 --EXPECTF--
 Warning: ini_set(): Invalid date.timezone value 'dummy' in %sbug73239.php on line %d
-DateTime::__construct(): Invalid date.timezone value 'dummy', we selected the timezone 'UTC' for now.
+DateTime::__construct(): UTC was used as timezone, because the date.timezone value 'dummy' is invalid

ext/date/tests/date_default_timezone_get-4.phpt

@@ -7,5 +7,5 @@ date.timezone=Incorrect/Zone
     echo date_default_timezone_get(), "\n";
 ?>
 --EXPECTF--
-Warning: date_default_timezone_get(): Invalid date.timezone value 'Incorrect/Zone', we selected the timezone 'UTC' for now. in %sdate_default_timezone_get-4.php on line %d
+Warning: date_default_timezone_get(): UTC was used as timezone, because the date.timezone value 'Incorrect/Zone' is invalid in %sdate_default_timezone_get-4.php on line %d
 UTC

ext/intl/tests/dateformat_invalid_timezone.phpt

@@ -16,4 +16,4 @@ try {
 }
 ?>
 --EXPECT--
-IntlDateFormatter::__construct(): Invalid date.timezone value 'Mars/Utopia_Planitia', we selected the timezone 'UTC' for now.
+IntlDateFormatter::__construct(): UTC was used as timezone, because the date.timezone value 'Mars/Utopia_Planitia' is invalid