Propagate KAT_ variables to tests
Propagate KAT_ variables to tests

Recently introduced KAT_CLIENT_DOCKER_IMAGE and
KAT_SERVER_DOCKER_IMAGE environment variables are not propagated
correctly leading to failures when running tests locally.

This commit fixes that so `make test` does not fail.

datawire/ambassador,datawire/ambassador,datawire/ambassador,datawire/ambassador,datawire/ambassador