Testing at scale

I'm part of a team building a relatively big platform that needs to be highly tests-covered.

With code-coverage: 1 hour of execution Without code-coverage: 10min of execution

The thing is that we are just at the beginning of the projet, in the next months with this tests-architectures I think we could get to 4-5hours of execution with code-coverage and 50min without.

The problem is that we want the run 100% of our tests to deploy, and sometimes we want to deploy very quickly our changes, then even 10min execution is already a lot of time.

I don't want to particularly explain our tests architecture, which is a lot about Symfony3, Phpunit, because the question is the following:

How big companies like Fb, Google manages to quickly run their ( compaired to us ) super massive tests bases quickly ? Do you have some docs that I must read absolutely ?

I already heard of distributed testing, etc.. But it is a bit fuzzy ..