Fix a bug where non-shell integration users would not get current directory...

Fix a bug where non-shell integration users would not get current directory recycling. If shell integration was never used then -[PTYSession currentLocalWorkingDirectory] would return nil. Issue 5634.

sources/PTYSession.m

@@ -8168,7 +8168,7 @@ ITERM_WEAKLY_REFERENCEABLE
 }
 - (NSString *)currentLocalWorkingDirectory {
-    if (_lastDirectoryIsRemote) {
+    if (_lastDirectoryIsRemote || _lastDirectory == nil) {
         // Ask the kernel what the child's process's working directory is.
         return [_shell getWorkingDirectory];
     } else {