MEMLEAK in test to reproduce issue `option_shutdown_anysegwit`

[enaples]

In a test to reproduce #9389 (PR #9390 )

two MEMLEAK occur:

**BROKEN** lightningd: MEMLEAK: 0x870c21e78
**BROKEN** lightningd:   label=u8[]
**BROKEN** lightningd:   alloc:
**BROKEN** lightningd:     channeld/channeld_wiregen.c:1570 (fromwire_channeld_got_shutdown)
**BROKEN** lightningd:     lightningd/channel_control.c:1300 (peer_got_shutdown)
**BROKEN** lightningd:     lightningd/channel_control.c:1633 (channel_msg)
**BROKEN** lightningd:   parents:
**BROKEN** lightningd:     struct channel

and

**BROKEN** lightningd: MEMLEAK: 0x8710392e8
**BROKEN** lightningd:   label=u8[]
**BROKEN** lightningd:   alloc:
**BROKEN** lightningd:     wire/peer_wiregen.c:2071 (towire_warning)
**BROKEN** lightningd:     common/wire_error.c:55 (towire_warningfmtv)
**BROKEN** lightningd:     common/wire_error.c:70 (towire_warningfmt)
**BROKEN** lightningd:     lightningd/channel_control.c:1314 (peer_got_shutdown)
**BROKEN** lightningd:     lightningd/channel_control.c:1633 (channel_msg)
**BROKEN** lightningd:   parents: