sql: Internal Error when executing query

**Describe the problem**

The latest version of the CockroachDB v24.2.0 encounters Internal Error when executing the following query:

```sql
CREATE TABLE v0 ( c1 ) AS ( WITH ta2 AS ( EXPLAIN COMMENT ON SCHEMA public IS NULL ) VALUES ( 0 ) );
```

**To Reproduce**

1. In operating system Ubuntu 20.04 LTS, download the pre-build CockroachDB binaries (v24.2.0) from [link](https://www.cockroachlabs.com/docs/releases/#v24-2)
2. Run `./cockroach demo`, and then paste the PoC query to the cockroach cli environment.
3. Observe the crash and log the stack information.

**Expected behavior**
The CockroachDB should return error from the statement.

**Additional data / screenshots**

This is the stack frame from the crash (v24.2.0):

```
ERROR: internal error: runtime error: invalid memory address or nil pointer dereference
SQLSTATE: XX000
DETAIL: stack trace:
github.com/cockroachdb/cockroach/pkg/util/errorutil/catch.go:29: ShouldCatch()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:225: func1()
GOROOT/src/runtime/panic.go:770: gopanic()
GOROOT/src/runtime/panic.go:261: panicmem()
GOROOT/src/runtime/signal_unix.go:881: sigpanic()
github.com/cockroachdb/cockroach/pkg/sql/schema_change_plan_node.go:59: SchemaChange()
github.com/cockroachdb/cockroach/pkg/sql/opaque.go:57: buildOpaque()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/opaque.go:70: tryBuildOpaque()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:467: buildStmt()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:299: buildStmtAtRootWithScope()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:280: buildStmtAtRoot()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/explain.go:31: buildExplain()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:389: buildStmt()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/with.go:198: buildCTE()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/with.go:143: buildCTEs()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/with.go:113: processWiths()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/select.go:1127: buildSelect()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:356: buildStmt()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:299: buildStmtAtRootWithScope()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:280: buildStmtAtRoot()
github.com/cockroachdb/cockroach/pkg/sql/opt/optbuilder/builder.go:259: Build()
github.com/cockroachdb/cockroach/pkg/sql/plan_opt.go:862: buildExecMemo()
github.com/cockroachdb/cockroach/pkg/sql/plan_opt.go:251: makeOptimizerPlan()
github.com/cockroachdb/cockroach/pkg/sql/schema_changer.go:381: 2()
github.com/cockroachdb/cockroach/pkg/sql/schema_resolver.go:444: runWithOptions()
github.com/cockroachdb/cockroach/pkg/sql/schema_changer.go:380: func2()
github.com/cockroachdb/cockroach/pkg/sql/internal.go:1940: func1()
github.com/cockroachdb/cockroach/pkg/sql/internal.go:2027: func4()
github.com/cockroachdb/cockroach/pkg/kv/txn.go:1049: exec()
github.com/cockroachdb/cockroach/pkg/kv/db.go:1103: runTxn()
github.com/cockroachdb/cockroach/pkg/kv/db.go:1066: TxnWithAdmissionControl()
github.com/cockroachdb/cockroach/pkg/kv/db.go:1041: Txn()
```

**Environment:**

- CockroachDB version: v24.2.0
- Server OS: Ubuntu 20.04 LTS
- Client app: CockroachDB demo command. (./cockroach demo)
- Detailed CockroachDB version output:

```
cockroach version details:
Build Tag: v24.2.0
Build Time: 2024/08/08 01:50:30
Distribution: CCL
Platform: linux arm64 (aarch64-unknown-linux-gnu)
Go Version: go1.22.5 X:nocoverageredesign
C Compiler: gcc 6.5.0
Build Commit ID: 953d09cce5a01cc0053e138516d80a27454f027c
Build Type: release
```

**Additional Information**

The bug is automatically reported when I am triggering it locally, in https://github.com/cockroachdb/cockroach/issues/131117 and https://github.com/cockroachdb/cockroach/issues/131118.

Jira issue: CRDB-42386