fix pointer conversion bug of go1.14

[yann-sjtu]

fixed 33cn/plugin#1003

开启race时默认开启checkptr，此时长度为n的[]byte只能转换为长度不超过 n/8的[]uint64，否则runtime检查会报错堆对象越界，导致unsafe强制类型转换失败。该pr用于修复plugin的单元测试报错

参考：
https://golang.org/src/runtime/checkptr.go?s=194:258#L1
etcd-io/bbolt#187
golang/go#34964
https://go-review.googlesource.com/c/net/+/203400/2/ipv4/control_bsd.go

[codecov]

Codecov Report

Merging #1063 (47540ce) into master (4b01e8a) will decrease coverage by 0.05%.
The diff coverage is 95.52%.

❗ Current head 47540ce differs from pull request most recent head 63fedad. Consider uploading reports for the commit 63fedad to get more accurate results

@@            Coverage Diff             @@
##           master    #1063      +/-   ##
==========================================
- Coverage   60.18%   60.12%   -0.06%     
==========================================
  Files         157      157              
  Lines       19817    19878      +61     
==========================================
+ Hits        11926    11952      +26     
- Misses       6073     6104      +31     
- Partials     1818     1822       +4     

Impacted Files	Coverage Δ
common/crypto/sha3/xor_unaligned.go	73.62% <95.52%> (-13.05%)	⬇️
system/crypto/secp256r1/utils.go	67.24% <0.00%> (-3.45%)	⬇️
blockchain/query_block.go	61.67% <0.00%> (-1.80%)	⬇️
blockchain/process.go	55.28% <0.00%> (-1.52%)	⬇️
blockchain/proc.go	32.22% <0.00%> (-0.89%)	⬇️
common/skiplist/skiplist.go	68.64% <0.00%> (-0.85%)	⬇️
rpc/jrpchandler.go	64.40% <0.00%> (-0.12%)	⬇️
blockchain/push.go	72.67% <0.00%> (ø)
blockchain/blockstore.go	58.73% <0.00%> (+0.10%)	⬆️

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[33cn]

🎉 This PR is included in version 1.66.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀

[33cn]

🎉 This PR is included in version 1.66.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀