Fix Windows and use "container" test group

This commit fixes the implementation on Windows and puts the
container integration tests in the container group again. The test for
long state paths will create files outside of the test directory.

It also cleans up the default folder used as state path.

internal/pkg/agent/cmd/container.go

@@ -780,7 +780,7 @@ func setPaths(statePath, configPath, logsPath, socketPath string, writePaths boo
 	// the statePath when concatenated with the socked name is going to
 	// be smaller than 104 characters.
 	if len(statePath) > 75 {
-		statePath = utils.SocketFallbackDirectory
+		statePath = utils.SocketURLWithFallback(statePath, paths.TempDir())
 	}
 
 	topPath := filepath.Join(statePath, "data")

testing/integration/container_cmd_test.go

@@ -106,7 +106,7 @@ func TestContainerCMD(t *testing.T) {
 		OS: []define.OS{
 			{Type: define.Linux},
 		},
-		Group: define.Default,
+		Group: "container",
 	})
 
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
@@ -164,7 +164,7 @@ func TestContainerCMDWithAVeryLongStatePath(t *testing.T) {
 		OS: []define.OS{
 			{Type: define.Linux},
 		},
-		Group: define.Default,
+		Group: "container",
 	})
 
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
@@ -182,6 +182,15 @@ func TestContainerCMDWithAVeryLongStatePath(t *testing.T) {
 	// so we join the workdir and a 120 characters long string.
 	statePath := filepath.Join(agentFixture.WorkDir(), "de9a2a338c4fe10a466ee9fae57ce0c8a5b010dfcd6bd3f41d2c569ef5ed873193fd7d1966a070174f47f93ee667f921616c2d6d29efb6dbcc2b8b33")
 
+	// We know it will use the OS temp folder for the state path, so we try
+	// to clean it up at the end of the test.
+	t.Cleanup(func() {
+		defaultStatePath := "/tmp/elastic-agent"
+		if err := os.RemoveAll(defaultStatePath); err != nil {
+			t.Errorf("could not remove config path '%s': %s", defaultStatePath, err)
+		}
+	})
+
 	enrollmentToken := createPolicy(t, ctx, agentFixture, info)
 	env := []string{
 		"FLEET_ENROLL=1",