Better coverage output, removing unnecessary unit scripts.

Signed-off-by: Silvin Lubecki <silvin.lubecki@docker.com>

scripts/test/unit

@@ -1,4 +0,0 @@
-#!/usr/bin/env bash
-set -eu -o pipefail
-
-gotestsum -- "$@"

scripts/test/unit-with-coverage

@@ -1,20 +0,0 @@
-#!/usr/bin/env bash
-set -eu -o pipefail
-
-# install test dependencies once before running tests for each package. This
-# reduces the runtime from 200s down to 23s
-go test -i "$@"
-
-echo "mode: atomic" > coverage.txt
-for pkg in "$@"; do
-    ./scripts/test/unit \
-        -cover \
-        -coverprofile=profile.out \
-        -covermode=atomic \
-        "${pkg}"
-
-    if test -f profile.out; then
-        grep -v "^mode:" < profile.out >> coverage.txt || true
-        rm profile.out
-    fi
-done