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>

internal/versionutil/init.go

@@ -0,0 +1,14 @@
+package versionutil
+
+import "github.com/nspcc-dev/neo-go/pkg/config"
+
+// TestVersion is a NeoGo version that should be used to keep all
+// compiled NEFs the same from run to run for tests.
+const TestVersion = "0.90.0-test"
+
+// init sets config.Version to a dummy TestVersion value to keep contract NEFs
+// consistent between test runs for those packages who import it. For test usage
+// only!
+func init() {
+	config.Version = TestVersion
+}