Move CALLF immediate argument validation to validate_instructions()

[gumb0]

Based on #663

Validating immediate argument is of CALLF shouldn't be part of stack validation, but rather instruction validation.

DATALOADN and RJUMPV (max_offset) arguments are already validated in validate_instructions() and #553 adds CREATE3 and RETURNCONTRACT there too, so it makes sense to have all these similar validations in one place.

[codecov]

Codecov Report

Merging #662 (0de4808) into master (6c08a08) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 0de4808 differs from pull request most recent head 698c0ec. Consider uploading reports for the commit 698c0ec to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #662   +/-   ##
=======================================
  Coverage   97.38%   97.39%           
=======================================
  Files          80       80           
  Lines        7964     7973    +9     
=======================================
+ Hits         7756     7765    +9     
  Misses        208      208           

Flag	Coverage Δ
blockchaintests	63.07% <0.00%> (-0.10%)	⬇️
statetests	74.00% <100.00%> (+0.02%)	⬆️
unittests	94.96% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
test/unittests/instructions_test.cpp	89.58% <ø> (ø)
lib/evmone/eof.cpp	83.42% <100.00%> (+0.13%)	⬆️
test/unittests/eof_validation_test.cpp	100.00% <100.00%> (ø)