[chore] Skip flaky test on Windows (open-telemetry#35302)

**Description:**
Since `receiver/googlecloudspanner` is unmaintained I'm opting to simply
skip the flaky test on Windows.

**Link to tracking Issue:**
Workaround for open-telemetry#32397

receiver/googlecloudspannerreceiver/internal/filter/itemcardinality_test.go

@@ -4,6 +4,7 @@
 package filter
 
 import (
+	"runtime"
 	"testing"
 	"time"
 
@@ -122,6 +123,9 @@ func TestItemCardinalityFilter_Shutdown(t *testing.T) {
 }
 
 func TestItemCardinalityFilter_Filter(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("Skipping test on Windows due to https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/32397")
+	}
 	items := initialItems(t)
 	logger := zaptest.NewLogger(t)
 	filter, err := NewItemCardinalityFilter(metricName, totalLimit, limitByTimestamp, itemActivityPeriod, logger)
@@ -175,6 +179,9 @@ func TestItemCardinalityFilter_Filter(t *testing.T) {
 }
 
 func TestItemCardinalityFilter_FilterItems(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("Skipping test on Windows due to https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/32397")
+	}
 	items := initialItemsWithSameTimestamp(t)
 	logger := zaptest.NewLogger(t)
 	filter, err := NewItemCardinalityFilter(metricName, totalLimit, limitByTimestamp, itemActivityPeriod, logger)