sql/tests: add "_test" suffix to file name

The commit renames a test file, `virtual_cluster_name.go`, to match the
naming convention. I believe the test in the was being run in CI before,
despite the misnaming.

Release note: None

pkg/sql/tests/BUILD.bazel

@@ -6,12 +6,10 @@ go_library(
         "command_filters.go",
         "data.go",
         "explain_test_util.go",
-        "virtual_cluster_name.go",
     ],
     importpath = "github.com/cockroachdb/cockroach/pkg/sql/tests",
     visibility = ["//visibility:public"],
     deps = [
-        "//pkg/base",
         "//pkg/internal/sqlsmith",
         "//pkg/kv",
         "//pkg/kv/kvpb",
@@ -20,10 +18,7 @@ go_library(
         "//pkg/sql/sem/tree",
         "//pkg/storage",
         "//pkg/testutils/serverutils",
-        "//pkg/testutils/sqlutils",
         "//pkg/testutils/storageutils",
-        "//pkg/util/leaktest",
-        "//pkg/util/log",
         "//pkg/util/syncutil",
         "@com_github_cockroachdb_errors//:errors",
         "@org_golang_x_text//cases",
@@ -62,6 +57,7 @@ go_test(
         "table_split_test.go",
         "tracing_sql_test.go",
         "truncate_test.go",
+        "virtual_cluster_name_test.go",
         "virtual_table_test.go",
     ],
     data = glob(["testdata/**"]) + [