[lldb] Fixed the test TestQuoting (llvm#91886)

os.path.join() uses the path separator of the host OS by default.
outfile_arg will be incorrect in case of Windows host and Linux target.
Use lldbutil.append_to_process_working_directory() instead.

Author: slydiman

lldb/test/API/commands/settings/quoting/TestQuoting.py

@@ -51,9 +51,7 @@ def expect_args(self, args_in, args_out):
         outfile = self.getBuildArtifact(filename)
 
         if lldb.remote_platform:
-            outfile_arg = os.path.join(
-                lldb.remote_platform.GetWorkingDirectory(), filename
-            )
+            outfile_arg = lldbutil.append_to_process_working_directory(self, filename)
         else:
             outfile_arg = outfile