Integration Test Scenario #4

spack still concretizies spack.yaml with oneapi compiler instead
of gcc. This test builds with --no-cache option to rule out spack.yaml
caching.
dev.Dockerfile has a CACHE_BUST arg for this purpose but it seems to be
set after copying spack.yaml not before. So if this works, move
CACHE_BUST before COPY instruction copying spack.