uaflex: avoid extra characters in lookahead

[Maxim Reznik]

There are situations when lexer generated by uaflex can avoid looking beyond right bound of the lexeme. If it's in a final state there is no transition by any next character, lexer should return result immediately.

Let's call such states 'dead-end' states and reorder them after any others. This avoid fast check is this state is dead-end.

We can also reorder other final states and place them before dead-ends, so we have continuous range of final states.

[Maxim Reznik]

In 5807:

In lexer generated by uaflex avoid extra looking

beyond right bound of the lexeme in dead-end states.

Close #488

[vadim.godunko]

Milestone renamed