gopls/internal/test/marker: skip on the freebsd race builder

The marker tests frequently time out on the freebsd race builder. Skip
them to reduce noise. (We don't currently have resources to
investigate).

Fixes golang/go#71731

Change-Id: I2e27c2e8063b6d5e698eb9d1b5c32d08914fcc77
Reviewed-on: https://go-review.googlesource.com/c/tools/+/651895
Auto-Submit: Robert Findley <rfindley@google.com>
Reviewed-by: Peter Weinberger <pjw@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: findleyr

gopls/internal/test/marker/marker_test.go

@@ -96,6 +96,9 @@ func Test(t *testing.T) {
 		if strings.HasPrefix(builder, "darwin-") || strings.Contains(builder, "solaris") {
 			t.Skip("golang/go#64473: skipping with -short: this test is too slow on darwin and solaris builders")
 		}
+		if strings.HasSuffix(builder, "freebsd-amd64-race") {
+			t.Skip("golang/go#71731: the marker tests are too slow to run on the amd64-race builder")
+		}
 	}
 	// The marker tests must be able to run go/packages.Load.
 	testenv.NeedsGoPackages(t)
@@ -658,7 +661,7 @@ type stringListValue []string
 
 func (l *stringListValue) Set(s string) error {
 	if s != "" {
-		for _, d := range strings.Split(s, ",") {
+		for d := range strings.SplitSeq(s, ",") {
 			*l = append(*l, strings.TrimSpace(d))
 		}
 	}
@@ -1838,7 +1841,7 @@ func removeDiagnostic(mark marker, loc protocol.Location, matchEnd bool, re *reg
 	diags := mark.run.diags[key]
 	for i, diag := range diags {
 		if re.MatchString(diag.Message) && (!matchEnd || diag.Range.End == loc.Range.End) {
-			mark.run.diags[key] = append(diags[:i], diags[i+1:]...)
+			mark.run.diags[key] = slices.Delete(diags, i, i+1)
 			return diag, true
 		}
 	}