Add an option to skip unsymbolicated class names.
Add an option to skip unsymbolicated class names.

Summary:
Add an option "--skip-unsymbolicated" to skip unsymbolicated names.
The script behavior does not change if the option is not added.

Reviewed By: thezhangwei

Differential Revision: D19666564

fbshipit-source-id: 49aca835730ce9296d32bcb72b0cc811fbe1ec9a

facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex