Improve e2e tests

[sdudoladov]

Speed up tests:

• increase VM size for builds
• cache build results

Fix the issue with the test runner sometimes failing to fetch the registry.opensource.zalan.do/acid/postgres-operator-e2e-tests:latest.
Description of the fix :

• There is no such image in the registry. In fact the image was never supposed to be there but was rather supposed to be rebuilt on every test run locally. So I removed the pull command for it
• The pull command was only executed if the image with the ${operator_tag} was not found locally.

1. The e2e image is built first with the clean working dir so it lacks the -dirty suffix added y git in VERSION ?= $(shell git describe --tags --always --dirty)
2. Makefile installs kind via go get. That from time to time modifies go.mod and go.sumand in that way pollutes the working dir.
3. The run.sh computes the image tag again, but this time the tag gets the -dirty suffix. So we actually have image-name locally, but try to fetch image-name-dirty, which obviuosly fails and the pull command from above is triggerd, and that fails as well. Installing kind manually removes the issue.

[Jan-M]

👍

[FxKu]

👎

The change to go modules made e2e tests independent from OS. I would prefer to keep that. Maybe some users out there are arleady relying on it. I understand that make e2e pollutes the operator repo. Can we maybe separate installing kind and running e2e tests? Maybe the tools section in operator makefile could also call the tools section from e2e test makefile.

[Jan-M]

👍

[FxKu]

👍