try more aggressive dropping

Author: swissspidy

src/DB_Command_SQLite.php

@@ -153,6 +153,8 @@ protected function sqlite_drop() {
 		if ( $wpdb instanceof \wpdb ) {
 			$wpdb->close();
 		}
+		unset( $wpdb );
+		gc_collect_cycles();
 
 		if ( ! unlink( $db_path ) ) {
 			WP_CLI::error( "Could not delete database file: {$db_path}" );
@@ -177,6 +179,8 @@ protected function sqlite_reset() {
 			if ( $wpdb instanceof \wpdb ) {
 				$wpdb->close();
 			}
+			unset( $wpdb );
+			gc_collect_cycles();
 
 			if ( ! unlink( $db_path ) ) {
 				WP_CLI::error( "Could not delete database file: {$db_path}" );