EVM: use more EVM style parameters for FVM syscall precompiles

[mriise]

mainly just assuming that everything is u256 encoded numbers... bleh

[codecov-commenter]

Codecov Report

Merging #837 (c1dca72) into next (eea22e0) will increase coverage by 0.03%.
The diff coverage is 0.00%.

❗ Current head c1dca72 differs from pull request most recent head 454bee5. Consider uploading reports for the commit 454bee5 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             next     #837      +/-   ##
==========================================
+ Coverage   87.28%   87.32%   +0.03%     
==========================================
  Files         125      125              
  Lines       22769    22769              
==========================================
+ Hits        19873    19882       +9     
+ Misses       2896     2887       -9     

Impacted Files	Coverage Δ
actors/evm/src/interpreter/precompiles.rs	87.55% <0.00%> (ø)
...ors/evm/src/interpreter/instructions/arithmetic.rs	73.28% <0.00%> (-0.69%)	⬇️
actors/eam/src/lib.rs	84.45% <0.00%> (-0.68%)	⬇️
actors/datacap/src/lib.rs	76.30% <0.00%> (-0.35%)	⬇️
state/src/check.rs	86.24% <0.00%> (-0.27%)	⬇️
actors/miner/src/lib.rs	83.36% <0.00%> (-0.06%)	⬇️
test_vm/src/lib.rs	82.90% <0.00%> (ø)
actors/miner/src/deadline_info.rs	96.62% <0.00%> (+16.85%)	⬆️