misc:runstat: add new method for MarketRunStat

Add fullPositions() to return if positions are full for MarketRunStat.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
strategy:turt1/turtle: avoid useless stable checkings to add position

Avoid useless stable price checkings to add position, which are quite
noisy to output logs.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>