Turn off transactions around Spree::Order state transitions.

Add failing test showing payment processing is set in a transaction.

Mark test of subclassed order as pending.

This test is now failing but it is unclear if it was ever really
testing what it claims to be testing. An order with no email
is not valid and should not save, so the test should not pass.

Add changelog entry.

Fixes #4542
Dont show out of stock for master product

We only care about variants stock for a product with variants