core: fix TestSubscriptions occasional failures
panic: Log in goroutine after TestSubscriptions has completed
goroutine 1079 [running]:
testing.(*common).logDepth(0xc00057a100, 0xc00039e210, 0xa4, 0x3)
/usr/local/go/src/testing/testing.go:634 +0x51a
testing.(*common).log(...)
/usr/local/go/src/testing/testing.go:614
testing.(*common).Logf(0xc00057a100, 0xe32eaa, 0x2, 0xc0009560e0, 0x1, 0x1)
/usr/local/go/src/testing/testing.go:649 +0x91
go.uber.org/zap/zaptest.testingWriter.Write(0xf64120, 0xc00057a100, 0x0, 0xc0003fe400, 0xa5, 0x400, 0xc000958e40, 0xc0009560d0, 0xc000958e60)
/go/pkg/mod/go.uber.org/zap@v1.10.0/zaptest/logger.go:130 +0x120
go.uber.org/zap/zapcore.(*ioCore).Write(0xc0005cd050, 0x0, 0xbfb54ffc0626aba2, 0x916de700, 0x1485500, 0x0, 0x0, 0xe43fb0, 0x1c, 0x0, ...)
/go/pkg/mod/go.uber.org/zap@v1.10.0/zapcore/core.go:90 +0x1c5
go.uber.org/zap/zapcore.(*CheckedEntry).Write(0xc000102d10, 0xc00039a000, 0x5, 0x5)
/go/pkg/mod/go.uber.org/zap@v1.10.0/zapcore/entry.go:215 +0x1e8
go.uber.org/zap.(*Logger).Info(0xc00035eba0, 0xe43fb0, 0x1c, 0xc00039a000, 0x5, 0x5)
/go/pkg/mod/go.uber.org/zap@v1.10.0/logger.go:187 +0x96
github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).persist(0xc00000cb40, 0xc00017c2c0, 0xbe8a00)
/go/src/github.com/nspcc-dev/neo-go/pkg/core/blockchain.go:839 +0x6c9
github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).Run.func2(0xc00000cb40, 0xc0005c6c30)
/go/src/github.com/nspcc-dev/neo-go/pkg/core/blockchain.go:302 +0x54
created by github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).Run
/go/src/github.com/nspcc-dev/neo-go/pkg/core/blockchain.go:301 +0x25d
FAIL github.com/nspcc-dev/neo-go/pkg/core 2.463s
c489f975d4