Remove unnecessary wrapper flags

Drop KUBE_GOFLAGS, KUBE_GOGCFLAGS, KUBE_GOLDFLAGS references
from the build infrastructure. There are some usages still
for KUBE_GOFLAGS, so we should print a deprecation message
until all those are fixed. If both KUBE_GOFLAGS and GOFLAGS
are just then we just bail out.

hack/make-rules/test-integration.sh

@@ -71,7 +71,7 @@ runTests() {
   # KUBE_RACE="-race"
   make -C "${KUBE_ROOT}" test \
       WHAT="${WHAT:-$(kube::test::find_integration_test_dirs | paste -sd' ' -)}" \
-      KUBE_GOFLAGS="${KUBE_GOFLAGS:-}" \
+      GOFLAGS="${GOFLAGS:-}" \
       KUBE_TEST_ARGS="${KUBE_TEST_ARGS:-} ${SHORT:--short=true} --vmodule=garbage*collector*=6 --alsologtostderr=true" \
       KUBE_RACE="" \
       KUBE_TIMEOUT="${KUBE_TIMEOUT}" \