use exports from ref-fvm

[LesnyRumcajs]

Summary of changes
Changes introduced in this pull request:

• used some exports from ref-fvm (from here plus some others on top of it), reducing code duplication a bit

Reference issue to close (if applicable)

Closes #1492

Other information and links

[codecov]

Codecov Report

Merging #1495 (1220f6a) into main (cf49ba7) will increase coverage by 0.10%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1495      +/-   ##
==========================================
+ Coverage   44.30%   44.40%   +0.10%     
==========================================
  Files         323      319       -4     
  Lines       28414    28231     -183     
==========================================
- Hits        12588    12537      -51     
+ Misses      15826    15694     -132     

Impacted Files	Coverage Δ
types/src/genesis/mod.rs	0.00% <ø> (ø)
types/src/lib.rs	57.14% <ø> (ø)
types/src/sector/post.rs	27.27% <ø> (ø)
blockchain/message_pool/src/msg_chain.rs	80.24% <0.00%> (-0.41%)	⬇️
vm/actor/src/builtin/miner/mod.rs	33.49% <0.00%> (-0.05%)	⬇️

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[lemmih]

Always great to see a PR that deletes a huge chunk of code. :)