tools: toolchain: run dbuild container with same timezone as host
tools: toolchain: run dbuild container with same timezone as host

Make it easier to work interactively by not reporting surprising times.

There are also reports that dtest fails with incorrect timezones, but those
are probably bugs in dtest.
Message-Id: <1946a2975f14b7cc6c4e345f4295ad4b453721cb@scylladb.com>

avikivity/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla