Allow for local --BUILDKIT_PROJECT when running RUN_EARTHLY tests (#3…

…989)

The BuildKit specified when running `+for-linux` and friends is not also
being used by `RUN_EARTHLY` tests which use the
`earthly-integration-test-base` image. This PR adds a similar argument
for tests based on the latter image.

```
earthly -P +test-no-qemu-group8 --BUILDKIT_PROJECT="../buildkit"
```

Earthfile

@@ -475,7 +475,7 @@ earthly-docker:
 # if no dockerhub mirror is not set it will attempt to login to dockerhub using the provided docker hub username and token.
 # Otherwise, it will attempt to login to the docker hub mirror using the provided username and password
 earthly-integration-test-base:
-    FROM +earthly-docker
+    FROM --pass-args +earthly-docker
     RUN apk update && apk add pcre-tools curl python3 bash perl findutils expect yq && apk add --upgrade sed
     COPY scripts/acbtest/acbtest scripts/acbtest/acbgrep /bin/
     ENV NO_DOCKER=1

tests/integration-base/Earthfile

@@ -8,14 +8,16 @@ test-base:
   ARG DOCKERHUB_MIRROR_AUTH=false
   ARG DOCKERHUB_MIRROR_AUTH_FROM_CLOUD_SECRETS=false
   ARG DOCKERHUB_AUTH=false
+  ARG BUILDKIT_PROJECT
 
   FROM ../..+earthly-integration-test-base \
     --DOCKERHUB_MIRROR=$DOCKERHUB_MIRROR \
     --DOCKERHUB_MIRROR_INSECURE=$DOCKERHUB_MIRROR_INSECURE \
     --DOCKERHUB_MIRROR_HTTP=$DOCKERHUB_MIRROR_HTTP \
     --DOCKERHUB_MIRROR_AUTH=$DOCKERHUB_MIRROR_AUTH \
     --DOCKERHUB_MIRROR_AUTH_FROM_CLOUD_SECRETS=$DOCKERHUB_MIRROR_AUTH_FROM_CLOUD_SECRETS \
-    --DOCKERHUB_AUTH=$DOCKERHUB_AUTH
+    --DOCKERHUB_AUTH=$DOCKERHUB_AUTH \
+    --BUILDKIT_PROJECT=$BUILDKIT_PROJECT
 
   # uncomment this to debug dockerhub rate-limiting issues
   #RUN if !grep "registry-1.docker.io.mirror.corp.earthly.dev" /root/.docker/config.json >/dev/null; then echo "The earthly mirror was not setup correctly" && exit 1; fi