Start gerrit server using StandaloneSiteTest and configure git client
connection using git-core client and SSH protocol.
Expand the tests for fetching tar archive and all supported compression
algorithms: gzip and bz2 in addition to xz.
Test Plan:
$ bazel test //javatests/com/google/gerrit/integration/git:upload-archive
Change-Id: I007fd3d736c2be5fdcae6f354752a3663c739ea9
da1b1ea72f