core: check methods offsets while contract deploying

[AnnaShaleva]

Close #2534 and port neo-project/neo-vm#476.

[codecov]

Codecov Report

Merging #2538 (1005c1f) into master (b6829f3) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2538      +/-   ##
==========================================
- Coverage   84.95%   84.95%   -0.01%     
==========================================
  Files         295      295              
  Lines       37144    37145       +1     
==========================================
  Hits        31556    31556              
- Misses       4246     4247       +1     
  Partials     1342     1342              

Impacted Files	Coverage Δ
pkg/core/interop/context.go	92.14% <100.00%> (ø)
pkg/core/native/management.go	92.39% <100.00%> (+0.01%)	⬆️
pkg/core/native/native_neo.go	81.79% <100.00%> (ø)
pkg/vm/context.go	88.12% <100.00%> (ø)
pkg/core/transaction/signer.go	75.00% <0.00%> (-12.50%)	⬇️
pkg/network/capability/capability.go	69.23% <0.00%> (-5.77%)	⬇️
pkg/network/message.go	94.02% <0.00%> (-2.24%)	⬇️
pkg/network/server.go	74.20% <0.00%> (+0.09%)	⬆️
pkg/network/tcp_transport.go	68.42% <0.00%> (+8.77%)	⬆️
... and 1 more

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