internal: avoid race access to config.Version by tests

Network server constructor reads config.Version variable, and
testcli.DeployContract writes dummy config.Version which causes
race in tests. Avoid this race by moving config.Version initialisation
to a separate package and perform it inside test packages init().

Close #3011, close #3017.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>

pkg/compiler/compiler_test.go

@@ -9,8 +9,8 @@ import (
 	"testing"
 
 	"github.com/nspcc-dev/neo-go/internal/random"
+	"github.com/nspcc-dev/neo-go/internal/versionutil"
 	"github.com/nspcc-dev/neo-go/pkg/compiler"
-	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/interop/native/neo"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
@@ -23,14 +23,15 @@ const examplePath = "../../examples"
 const exampleCompilePath = "testdata/compile"
 const exampleSavePath = exampleCompilePath + "/save"
 
+// Keep contract NEFs consistent between runs.
+const _ = versionutil.TestVersion
+
 type compilerTestCase struct {
 	name     string
 	function func(*testing.T)
 }
 
 func TestCompiler(t *testing.T) {
-	// CompileAndSave uses config.Version for proper .nef generation.
-	config.Version = "0.90.0-test"
 	testCases := []compilerTestCase{
 		{
 			name: "TestCompileDirectory",