build: add crdb_bench flag

A recent change (cockroachdb#148576) causes some test initializations to throw a panic if
the binary was not build with `crdb_test`.

```
./dev bench pkg/sql/catalog/lease -f=BenchmarkAcquireLeaseConcurrent
$ bazel test pkg/sql/catalog/lease:all --nocache_test_results --test_arg -test.run=- --test_arg -test.bench=BenchmarkAcquireLeaseConcurrent --test_sharding_strategy=disabled --test_arg -test.cpu --test_arg 1 --test_arg -test.benchmem --crdb_test_off --test_env COCKROACH_TEST_FIXTURES_DIR=/Users/herko/Library/Caches/crdb-test-fixtures --sandbox_writable_path=/Users/herko/Library/Caches/crdb-test-fixtures --test_output streamed

panic: Testing override for schema_locked used in non-test binary.

goroutine 1 [running]:
github.com/cockroachdb/cockroach/pkg/sql.TestForceDisableCreateTableWithSchemaLocked(...)
	pkg/sql/exec_util.go:773
github.com/cockroachdb/cockroach/pkg/sql/catalog/lease_test.TestMain(0x1400132e620?)
	pkg/sql/catalog/lease/main_test.go:29 +0xcc
main.main()
```

This is problematic for benchmarks, which are not built with `crdb_test`.
Benchmarks are not built with the `crdb_test` flag, because this flag enables
metamorphic variables and extra assertions which could interfere with
performance testing.

This change adds a new `crdb_bench` flag, which is disabled by default. The
assertions added in cockroachdb#148576 is now also skipped when `crdb_bench` is enabled.

Informs: cockroachdb#148576
Fixes: cockroachdb#149339

Epic: None
Release note: None

Author: herkolategan

.bazelrc

@@ -22,6 +22,7 @@ startup --host_jvm_args=-DBAZEL_TRACK_SOURCE_DIRECTORIES=1
 build --flag_alias=bazel_code_coverage=//build/toolchains:bazel_code_coverage_flag
 build --flag_alias=crdb_test=//build/toolchains:crdb_test_flag
 build --flag_alias=crdb_test_off=//build/toolchains:crdb_test_off_flag
+build --flag_alias=crdb_bench=//build/toolchains:crdb_bench_flag
 build --flag_alias=cross=//build/toolchains:cross_flag
 build --flag_alias=dev=//build/toolchains:dev_flag
 build --flag_alias=force_build_cdeps=//build/toolchains:force_build_cdeps_flag

build/toolchains/BUILD.bazel

@@ -299,6 +299,19 @@ config_setting(
     },
 )
 
+bool_flag(
+    name = "crdb_bench_flag",
+    build_setting_default = False,
+    visibility = ["//visibility:public"],
+)
+
+config_setting(
+    name = "crdb_bench",
+    flag_values = {
+        ":crdb_bench_flag": "true",
+    },
+)
+
 bool_flag(
     name = "dev_flag",
     build_setting_default = False,

pkg/util/buildutil/BUILD.bazel

@@ -1,5 +1,7 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
+# gazelle:exclude gen-crdb_bench_off.go
+# gazelle:exclude gen-crdb_bench_on.go
 # gazelle:exclude gen-crdb_test_off.go
 # gazelle:exclude gen-crdb_test_on.go
 
@@ -9,13 +11,30 @@ go_library(
     srcs = select({
         "//build/toolchains:crdb_test": [":gen-crdb-test-on"],
         "//conditions:default": [":gen-crdb-test-off"],
+    }) + select({
+        "//build/toolchains:crdb_bench": [":gen-crdb-bench-on"],
+        "//conditions:default": [":gen-crdb-bench-off"],
     }),
     importpath = "github.com/cockroachdb/cockroach/pkg/util/buildutil",
     visibility = ["//visibility:public"],
 )
 
 REMOVE_GO_BUILD_CONSTRAINTS = "cat $< | grep -v '//go:build' | grep -v '// +build' > $@"
 
+genrule(
+    name = "gen-crdb-bench-on",
+    srcs = ["crdb_bench_on.go"],
+    outs = ["gen-crdb_bench_on.go"],
+    cmd = REMOVE_GO_BUILD_CONSTRAINTS,
+)
+
+genrule(
+    name = "gen-crdb-bench-off",
+    srcs = ["crdb_bench_off.go"],
+    outs = ["gen-crdb_bench_off.go"],
+    cmd = REMOVE_GO_BUILD_CONSTRAINTS,
+)
+
 genrule(
     name = "gen-crdb-test-on",
     srcs = ["crdb_test_on.go"],

pkg/util/buildutil/crdb_bench_off.go

@@ -0,0 +1,13 @@
+// Copyright 2025 The Cockroach Authors.
+//
+// Use of this software is governed by the CockroachDB Software License
+// included in the /LICENSE file.
+
+//go:build !crdb_bench || crdb_bench_off
+
+// Package buildutil provides a constant CrdbBenchBuild.
+package buildutil
+
+// CrdbBenchBuild is a flag that is set to true if the binary was compiled
+// with the 'crdb_bench' build tag (which is the case for all benchmark targets).
+const CrdbBenchBuild = false

pkg/util/buildutil/crdb_bench_on.go

@@ -0,0 +1,13 @@
+// Copyright 2025 The Cockroach Authors.
+//
+// Use of this software is governed by the CockroachDB Software License
+// included in the /LICENSE file.
+
+//go:build crdb_bench && !crdb_bench_off
+
+// Package buildutil provides a constant CrdbBenchBuild.
+package buildutil
+
+// CrdbBenchBuild is a flag that is set to true if the binary was compiled
+// with the 'crdb_bench' build tag (which is the case for all benchmark targets).
+const CrdbBenchBuild = true