Revert "lex: enable user-defined refill action"
This reverts commit e55022a06a5ac3ed8fb5b90cd90803a2416fd2a7.

Revert "lex: cleanup whitespaces, no semantic changes"
This reverts commit 5fb86606a83576ee5fbc0feb5625b08bb4f650a3.
Add global refill action