asim: run no_rand tests in parallel

Each simulation is single-threaded, so it makes sense to evaluate different
testfiles in parallel.

A complication is that each simulation logs using our default logging library,
and since that is a singleton, we can't provide each simulation with its own
logger. When a subtest is a parallel test (as is the case here), it waits for
the parent test to return before running. This means that the `log.Scope` in
`TestDataDriven` would be cleaned up by the time the parallel subtests would
actually start simulating. I'm avoiding this by creating the scope, but then
releasing it via `t.Cleanup`, which only runs when all subtests have completed.
Something similar is done with `leaktest.AfterTest`.

```
./dev test pkg/kv/kvserver/asim/tests  -f 'TestDataDriven'  --ignore-cache --rewrite  -v -- --test_env COCKROACH_RUN_ASIM_TESTS=true
//pkg/kv/kvserver/asim/tests:tests_test                                  PASSED in 202.1s # before
//pkg/kv/kvserver/asim/tests:tests_test                                  PASSED in 60.6s  # after
```

Epic: CRDB-25222

Author: tbg

pkg/kv/kvserver/asim/tests/BUILD.bazel

@@ -56,6 +56,7 @@ go_test(
         "//pkg/util/leaktest",
         "//pkg/util/log",
         "@com_github_cockroachdb_datadriven//:datadriven",
+        "@com_github_cockroachdb_logtags//:logtags",
         "@com_github_stretchr_testify//require",
         "@org_gonum_v1_plot//:plot",
         "@org_gonum_v1_plot//plotter",

pkg/kv/kvserver/asim/tests/datadriven_simulation_test.go

@@ -35,6 +35,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/util/leaktest"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
 	"github.com/cockroachdb/datadriven"
+	"github.com/cockroachdb/logtags"
 	"github.com/stretchr/testify/require"
 	"gonum.org/v1/plot"
 	"gonum.org/v1/plot/plotter"
@@ -182,16 +183,27 @@ var runAsimTests = envutil.EnvOrDefaultBool("COCKROACH_RUN_ASIM_TESTS", false)
 //     ..US_3
 //     ....└── [11 12 13 14 15]
 func TestDataDriven(t *testing.T) {
-	defer leaktest.AfterTest(t)()
-	defer log.Scope(t).Close(t)
 	skip.UnderDuressWithIssue(t, 149875)
-	ctx := context.Background()
+	leakTestAfter := leaktest.AfterTest(t)
 	dir := datapathutils.TestDataPath(t, "non_rand")
+
+	// NB: we must use t.Cleanup instead of deferring this
+	// cleanup in the main test due to the use of t.Parallel
+	// below.
+	// See https://github.com/golang/go/issues/31651.
+	scope := log.Scope(t)
+	t.Cleanup(func() {
+		scope.Close(t)
+		leakTestAfter()
+	})
 	datadriven.Walk(t, dir, func(t *testing.T, path string) {
 		if filepath.Ext(path) != ".txt" {
 			return
 		}
-		plotNum := 0
+		ctx := logtags.AddTag(context.Background(), "name", filepath.Base(path))
+		// The inline comment below is required for TestLint/TestTParallel.
+		// We use t.Cleanup to work around the issue this lint is trying to prevent.
+		t.Parallel() // SAFE FOR TESTING
 		const defaultKeyspace = 10000
 		loadGen := gen.MultiLoad{}
 		var clusterGen gen.ClusterGen
@@ -200,7 +212,8 @@ func TestDataDriven(t *testing.T) {
 		eventGen := gen.NewStaticEventsWithNoEvents()
 		assertions := []assertion.SimulationAssertion{}
 		var stateStrAcrossSamples []string
-		runs := []history.History{}
+		var runs []history.History
+		plotNum := 0
 		datadriven.RunTest(t, path, func(t *testing.T, d *datadriven.TestData) string {
 			defer func() {
 				require.Empty(t, d.CmdArgs, "leftover arguments for %s", d.Cmd)