Improve cpimport ingest speed into Dictionary columns

Given 800 000 000 records with a couple Dictionary columns with lots of equal length strings in the data set. It took 4 167 seconds to ingest the data set into CS.
After the patch it takes only 467 seconds.

There were two main sources of latency:

• Dctnry::getTokenFromArray represented de-dup buffer as array and called memcpy for any equal-sized string
• COND_WAIT_SECONDS was 3 seconds per default