[lldb][NFC] use platform independent path separator in testSettings.py. (#132392)

The build bot was failing when running remote test from windows to
linux.

From  #131683

---------

Signed-off-by: Ebuka Ezike <[email protected]>
Co-authored-by: Pavel Labath <[email protected]>

Author: da-viper

lldb/test/API/commands/settings/TestSettings.py

@@ -1018,8 +1018,9 @@ def test_settings_api(self):
 
         # Test OptionValueFileSpec and OptionValueFileSpecList
         setting_path = "target.debug-file-search-paths"
-        setting_value = ["/tmp" "/tmp2"]
-        self.runCmd("settings set %s %s" % (setting_path, " ".join(setting_value)))
+        path1 = os.path.join(self.getSourceDir(), "tmp")
+        path2 = os.path.join(self.getSourceDir(), "tmp2")
+        self.runCmd("settings set %s '%s' '%s'" % (setting_path, path1, path2))
         settings_json = self.get_setting_json(setting_path)
         self.assertEqual(settings_json, setting_value)