Keep the store address's query in every test database's address, so store tests reach a socket-addressed store (issue 1889)

The checker's integration store answers on a unix socket named in the query of MESH_TEST_POSTGRES
(?host=<socket dir>&sslmode=disable). The identity, inventory and licences fixtures cut the address at
its last slash and appended ?sslmode=disable, dropping host=, so pgx dialled its default socket where no
server is: every store test waited out its 20 s readiness bound, each package ran into go test's
10-minute timeout, and the verdict named only the first failure,
identity.TestACertificateChainsToTheMeshsOwnAuthority.

store.DatabaseForTest now builds that address for every fixture, keeping the query as the template raise
already did; identity's fresh is ForTest rather than a second copy. The readiness bound and its error,
which wraps the driver's cause, are unchanged.

internal/inventory/fortest.go

@@ -42,8 +42,7 @@ func ForTest(t *testing.T) *Inventory {
 	store.CreateMigratedForTest(t, admin, name, migrations)
 	busPasswordCostForTest.Store(int32(bcrypt.MinCost))
 
-	cut := strings.LastIndex(admin, "/")
-	t.Setenv(store.Variable(Name), admin[:cut]+"/"+name+"?sslmode=disable")
+	t.Setenv(store.Variable(Name), store.DatabaseForTest(admin, name))
 
 	inv, err := Open(t.Context())
 	if err != nil {
@@ -113,8 +112,7 @@ func ForTestBefore(t *testing.T, number int) (*Inventory, func()) {
 	}
 	store.CreateMigratedForTest(t, admin, name, before)
 	busPasswordCostForTest.Store(int32(bcrypt.MinCost))
-	cut := strings.LastIndex(admin, "/")
-	t.Setenv(store.Variable(Name), admin[:cut]+"/"+name+"?sslmode=disable")
+	t.Setenv(store.Variable(Name), store.DatabaseForTest(admin, name))
 	inv, err := Open(t.Context())
 	if err != nil {
 		t.Fatal(err)