Yes, I was hired at Google to do dedicated testing (Test Engineer was my title). Note that at Google, many test engineers were "supposed to" build test infra, not write tests or do testing. I was brought on to test some systems that were critically important, but built by a team that focused more on operations than coding. I set up a continuous build, fixed all the broken tests, and prevented team members from checking in broken code. I don't think developers can be entirely trusted to QA their code.