panic when calling AssignedWithdraw with contractAddress as withdraw address

[KarlChristomer]

Describe the bug briefly
Panic occurs when calling AssignedWithdraw method in inner Fund contract with contractAddress as withdraw address.

Information

• logs

goroutine 239 [running]:
github.com/vitelabs/go-vite/v2/common.catch()
	/home/runner/work/go-vite-nightly/go-vite-nightly/common/goroutine.go:36 +0x465
panic(0x19ce5a0, 0xc0157fbfa0)
	/opt/hostedtoolcache/go/1.16.15/x64/src/runtime/panic.go:965 +0x1b9
github.com/vitelabs/go-vite/v2/ledger/onroad.(*Manager).InsertAccountBlocks(0xc0143fc480, 0xc00000e288, 0x1, 0x1, 0x0, 0x0)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/onroad/chain_events.go:52 +0xa29
github.com/vitelabs/go-vite/v2/ledger/chain.(*eventManager).TriggerInsertAbs(0xc0001105d0, 0xc00000d402, 0xc00000e288, 0x1, 0x1, 0x0, 0x0)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/chain/event_manager.go:59 +0xfa
github.com/vitelabs/go-vite/v2/ledger/chain.(*chain).InsertAccountBlock(0xc000224000, 0xc00000d4a0, 0x0, 0x0)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/chain/insert.go:41 +0x365
github.com/vitelabs/go-vite/v2/ledger/pool.(*accountCh).insertBlock(0xc015c98a00, 0x20dbfc8, 0xc0157ca310, 0xf, 0x4)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/pool/tools_chain.go:78 +0x4ac
github.com/vitelabs/go-vite/v2/ledger/pool.(*accountPool).verifySuccess(0xc015cc0540, 0xc0157ca310, 0xf, 0xc0005d3ec0, 0x4)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/pool/account_pool.go:182 +0x52
github.com/vitelabs/go-vite/v2/ledger/pool.(*accountPool).AddDirectBlocks(0xc015cc0540, 0xc0157ca2a0, 0x0, 0x0)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/pool/account_pool.go:258 +0x585
github.com/vitelabs/go-vite/v2/ledger/pool.(*pool).AddDirectAccountBlock(0xc0143cc000, 0x0, 0x0, 0x106000000, 0xc00000d380, 0x0, 0x0)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/pool/pool.go:395 +0x62c
github.com/vitelabs/go-vite/v2/ledger/onroad.(*Manager).insertBlockToPool(...)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/onroad/access.go:54
github.com/vitelabs/go-vite/v2/ledger/onroad.(*ContractTaskProcessor).processOneAddress(0xc015577280, 0xc015f01c80, 0x0)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/onroad/taskprocessor.go:129 +0x1742
github.com/vitelabs/go-vite/v2/ledger/onroad.(*ContractTaskProcessor).work(0xc015577280)
	/home/runner/work/go-vite-nightly/go-vite-nightly/ledger/onroad/taskprocessor.go:49 +0x3a6
github.com/vitelabs/go-vite/v2/common.wrap(0xc015c35fe0)
	/home/runner/work/go-vite-nightly/go-vite-nightly/common/goroutine.go:19 +0x49
created by github.com/vitelabs/go-vite/v2/common.Go
	/home/runner/work/go-vite-nightly/go-vite-nightly/common/goroutine.go:14 +0x3