Faster client-side query parsing in ClientParser and NativeSql

Client-side prepared statements parse the SQL on every prepareStatement (text protocol) to locate
parameter markers, strings, comments and INSERT ... VALUES / ON DUPLICATE keywords, and
Connection.nativeSQL / escape processing lexes the text again to resolve

{fn ...}, {ts ...} 

escapes.

Both lexers were byte-at-a-time state machines doing several comparisons per byte. They are rewritten
to skip ordinary bytes through a 256-entry lookup table and to consume strings, backtick identifiers
and comments in tight inner loops, with the same results as before (same unit test corpus).