build-unit-test-docker.sh: Extract specific commits when not using ubuntu package

See discussion in https://gerrit.openbmc-project.xyz/#/c/openbmc/openbmc-build-scripts/+/13220/4/build-unit-test-docker.sh@247

Should make sure we do this for all packages and also we need to stop doing the extract/build in the previous jobs make directory (i.e. go back to $HOME).