cli: do not run test server on windows

Currently we can't properly stop running server on Windows and SIGHUP
is also not supported. This leads to occupied resources and failed
test cleanup:
```
--- FAIL: TestServerStart (0.35s)
    --- FAIL: TestServerStart/good (0.10s)
        testing.go:894: TempDir RemoveAll cleanup: remove C:\Users\Anna\AppData\Local\Temp\TestServerStart_good337747932\001\neogotestchain\000001.log:
The process cannot access the file because it is being used by another process.
2022-02-08T14:11:20.959+0300    INFO    persisted to disk       {"blocks": 0, "keys": 112, "headerHeight": 0, "blockHeight": 0, "took": "10.0049ms"}
```

cli/server_test.go

@@ -1,11 +1,11 @@
 package main
 
 import (
-	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -96,6 +96,9 @@ func TestServerStart(t *testing.T) {
 			e.RunWithError(t, baseCmd...)
 		})
 	})
+	// We can't properly shutdown server on windows and release the resources.
+	// Also, windows doesn't support SIGHUP and SIGINT.
+	if runtime.GOOS != "windows" {
 		t.Run("good", func(t *testing.T) {
 			saveCfg(t, func(cfg *config.Config) {})
 
@@ -107,7 +110,7 @@ func TestServerStart(t *testing.T) {
 			require.Eventually(t, func() bool {
 				line, err = e.Out.ReadString('\n')
 				if err != nil && err != io.EOF {
-				t.Fatalf(fmt.Sprintf("unexpected error while reading CLI output: %s", err))
+					t.Fatalf("unexpected error while reading CLI output: %s", err)
 				}
 				return err == nil
 			}, 2*time.Second, 100*time.Millisecond)
@@ -121,4 +124,5 @@ func TestServerStart(t *testing.T) {
 			e.checkNextLine(t, "")
 			e.checkEOF(t)
 		})
+	}
 }