Ensure the check command do not panic

[ahrtr]

When a db file is corrupted, usually we depend on the check command to diagnose the db file. But if the check command also crashes/panics, then it won't be able to provide any useful diagnosis info.

So we should ensure the check command doesn't panic.

[ishan16696]

I can work on this, can you assign this issue to me @ahrtr ?

[ahrtr]

Thanks @ishan16696 . Please feel free to provide a PoC firstly.

[ishan16696]

I'm able to reproduce this issue by corrupting the bolt db file on some leaf pages which lead to check command panic

> ./bbolt check ~/bbolt/default.etcd.test/member/snap/db

panic: assertion failed: Page expected to be: 7, but self identifies as 0

goroutine 5 [running]:
go.etcd.io/bbolt/internal/common.Assert(...)
	~/go/src/backup_forked/bbolt/internal/common/verify.go:65
go.etcd.io/bbolt/internal/common.(*Page).FastCheck(0x10b474000, 0x7)
	~/go/src/backup_forked/bbolt/internal/common/page.go:83 +0x188
go.etcd.io/bbolt.(*Tx).page(0x14000058c68?, 0x10431950c?)
	~/go/src/backup_forked/bbolt/tx.go:539 +0x74
go.etcd.io/bbolt.(*Tx).forEachPageInternal(0x14000058d58?, {0x140000180a0?, 0x1, 0xa}, 0x14000058d28)
	~/go/src/backup_forked/bbolt/tx.go:551 +0x50
go.etcd.io/bbolt.(*Tx).forEachPage(...)
	~/go/src/backup_forked/bbolt/tx.go:547
go.etcd.io/bbolt.(*Tx).checkBucket(0x1400010e000, 0x1400010e018, 0x14000058ea8, 0x14000058ed8, {0x104577818?, 0x1047053a0}, 0x14000022060)
	~/go/src/backup_forked/bbolt/tx_check.go:100 +0xc8
go.etcd.io/bbolt.(*Tx).check(0x1400010e000, {0x104577818, 0x1047053a0}, 0x0?)
	~/go/src/backup_forked/bbolt/tx_check.go:78 +0x288
created by go.etcd.io/bbolt.(*Tx).Check in goroutine 1
	~/go/src/backup_forked/bbolt/tx_check.go:30 +0x124