Cache UoM and Product in stock.move create
Stock move's create() can get a performance boost by caching Uom and Product instances:
https://hg.tryton.org/modules/stock/file/tip/move.py#l727
A test on the proposted review reduces the time from 19s to 15s to create several moves. The measured reduction will greatly depend on the number of product and uoms that are repeated in the vlist.