Nested delimited strings had an infinite loop.
Nested delimited strings had an infinite loop.

The code for nested and unnested strings was mixed, thereby being too
simple for the nested case. I separated them, which is simpler than
the fixed combined version.
Detected by the macro call
        ..EMIT <$FAC=^D<fb$rea>>

Rhialto/macro11,Rhialto/macro11,Rhialto/macro11