Site Health: Check if session_status() exists before calling it.

Merges [48742] to the 5.5 branch.
Reviewed by desrosj, SergeyBiryukov.
Props bgermann.
Fixes #50862.
Built from https://develop.svn.wordpress.org/branches/5.5@48746


git-svn-id: http://core.svn.wordpress.org/branches/5.5@48508 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-wp-site-health.php

@@ -1115,7 +1115,7 @@ class WP_Site_Health {
 			'test'        => 'php_sessions',
 		);
 
-		if ( PHP_SESSION_ACTIVE === session_status() ) {
+		if ( function_exists( 'session_status' ) && PHP_SESSION_ACTIVE === session_status() ) {
 			$result['status'] = 'critical';
 
 			$result['label'] = __( 'An active PHP session was detected' );

wp-admin/includes/file.php

@@ -555,7 +555,7 @@ function wp_edit_theme_plugin_file( $args ) {
 			$url = admin_url();
 		}
 
-		if ( PHP_SESSION_ACTIVE === session_status() ) {
+		if ( function_exists( 'session_status' ) && PHP_SESSION_ACTIVE === session_status() ) {
 			// Close any active session to prevent HTTP requests from timing out
 			// when attempting to connect back to the site.
 			session_write_close();

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-RC2-48740';
+$wp_version = '5.5-RC2-48746';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.