Skip TestHealthKillContainer on Windows

This test is failing on Windows currently:

```
11:59:47 --- FAIL: TestHealthKillContainer (8.12s)
11:59:47     health_test.go:57: assertion failed: error is not nil: Error response from daemon: Invalid signal: SIGUSR1
``

That test was added recently in https://github.com/moby/moby/pull/39454, but
rewritten in a commit in the same PR:
f8aef6a92f

In that rewrite, there were some changes:

- originally it was skipped on Windows, but the rewritten test doesn't have that skip:

    ```go
    testRequires(c, DaemonIsLinux) // busybox doesn't work on Windows
    ```

- the original test used `SIGINT`, but the new one uses `SIGUSR1`

Analysis:

- The Error bubbles up from: 8e610b2b55/pkg/signal/signal.go (L29-L44)
- Interestingly; `ContainerKill` should validate if a signal is valid for the given platform, but somehow we don't hit that part; f1b5612f20/daemon/kill.go (L40-L48)
- Windows only looks to support 2 signals currently 8e610b2b55/pkg/signal/signal_windows.go (L17-L26)
- Upstream Golang looks to define `SIGINT` as well; 77f9b2728e/src/runtime/defs_windows.go (L44)
- This looks like the current list of Signals upstream in Go; 3b58ed4ad3/windows/types_windows.go (L52-L67)

```go
const (
	// More invented values for signals
	SIGHUP  = Signal(0x1)
	SIGINT  = Signal(0x2)
	SIGQUIT = Signal(0x3)
	SIGILL  = Signal(0x4)
	SIGTRAP = Signal(0x5)
	SIGABRT = Signal(0x6)
	SIGBUS  = Signal(0x7)
	SIGFPE  = Signal(0x8)
	SIGKILL = Signal(0x9)
	SIGSEGV = Signal(0xb)
	SIGPIPE = Signal(0xd)
	SIGALRM = Signal(0xe)
	SIGTERM = Signal(0xf)
)
```

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit eeaa0b30d4)
Signed-off-by: Dani Louca <dani.louca@docker.com>

integration/container/health_test.go

@@ -36,6 +36,7 @@ func TestHealthCheckWorkdir(t *testing.T) {
 // GitHub #37263
 // Do not stop healthchecks just because we sent a signal to the container
 func TestHealthKillContainer(t *testing.T) {
+	skip.If(t, testEnv.OSType == "windows", "Windows only supports SIGKILL and SIGTERM? See https://github.com/moby/moby/issues/39574")
 	defer setupTest(t)()
 
 	ctx := context.Background()