fix: Move types/test_util.go:MakeBlock into types/block.go

[tnasu]

Description

The production code of types.MakeBlock is defined in types/test_util.go. It is used for state.MakeBlock only. I move it into types/block.go

[codecov]

Codecov Report

Merging #490 (465b0c4) into main (955cfde) will decrease coverage by 0.06%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #490      +/-   ##
==========================================
- Coverage   65.56%   65.50%   -0.07%     
==========================================
  Files         278      278              
  Lines       37927    37927              
==========================================
- Hits        24867    24843      -24     
- Misses      11251    11280      +29     
+ Partials     1809     1804       -5     

Impacted Files	Coverage Δ
types/test_util.go	72.72% <ø> (-5.54%)	⬇️
types/block.go	73.56% <100.00%> (+0.41%)	⬆️
blockchain/v0/pool.go	78.81% <0.00%> (-5.69%)	⬇️
p2p/pex/pex_reactor.go	79.67% <0.00%> (-1.85%)	⬇️
consensus/reactor.go	74.84% <0.00%> (-1.51%)	⬇️
consensus/msgs.go	84.19% <0.00%> (-0.92%)	⬇️
blockchain/v0/reactor.go	69.49% <0.00%> (-0.68%)	⬇️
proxy/multi_app_conn.go	47.66% <0.00%> (ø)
consensus/state.go	73.61% <0.00%> (+0.29%)	⬆️
light/client.go	62.05% <0.00%> (+0.44%)	⬆️
... and 4 more