Make atomic updateAll / deleteAll return the affected rows instead of bool

Resolves https://github.com/cakephp/cakephp/issues/5371

As side-effect of strict asserts I found out that sqlite doesnt really return int where it should:

    Failed asserting that '3' is identical to 3.

 Fixed along with it.
See my remark in the initial comment. Yes, it is a string integer here.