restore filter tags that git cherry-pick reverted

Signed-off-by: Tim Vaillancourt <tim@timvaillancourt.com>

go/vt/discovery/healthcheck.go

@@ -320,6 +320,9 @@ func NewVTGateHealthCheckFilters() (filters TabletFilters, err error) {
 	} else if len(KeyspacesToWatch) > 0 {
 		filters = append(filters, NewFilterByKeyspace(KeyspacesToWatch))
 	}
+	if len(tabletFilterTags) > 0 {
+		filters = append(filters, NewFilterByTabletTags(tabletFilterTags))
+	}
 	return filters, nil
 }
 

go/vt/discovery/healthcheck_test.go

@@ -67,12 +67,14 @@ func TestNewVTGateHealthCheckFilters(t *testing.T) {
 	defer func() {
 		KeyspacesToWatch = nil
 		tabletFilters = nil
+		tabletFilterTags = nil
 	}()
 
 	testCases := []struct {
 		name                string
 		keyspacesToWatch    []string
 		tabletFilters       []string
+		tabletFilterTags    map[string]string
 		expectedError       string
 		expectedFilterTypes []any
 	}{
@@ -89,6 +91,18 @@ func TestNewVTGateHealthCheckFilters(t *testing.T) {
 			keyspacesToWatch:    []string{"ks1"},
 			expectedFilterTypes: []any{&FilterByKeyspace{}},
 		},
+		{
+			name:                "tabletFiltersAndTags",
+			tabletFilters:       []string{"ks1|-80"},
+			tabletFilterTags:    map[string]string{"test": "true"},
+			expectedFilterTypes: []any{&FilterByShard{}, &FilterByTabletTags{}},
+		},
+		{
+			name:                "keyspacesToWatchAndTags",
+			tabletFilterTags:    map[string]string{"test": "true"},
+			keyspacesToWatch:    []string{"ks1"},
+			expectedFilterTypes: []any{&FilterByKeyspace{}, &FilterByTabletTags{}},
+		},
 		{
 			name:             "failKeyspacesToWatchAndFilters",
 			tabletFilters:    []string{"ks1|-80"},
@@ -106,6 +120,7 @@ func TestNewVTGateHealthCheckFilters(t *testing.T) {
 		t.Run(testCase.name, func(t *testing.T) {
 			KeyspacesToWatch = testCase.keyspacesToWatch
 			tabletFilters = testCase.tabletFilters
+			tabletFilterTags = testCase.tabletFilterTags
 
 			filters, err := NewVTGateHealthCheckFilters()
 			if testCase.expectedError != "" {