chore: add empty test files for consistent coverage

[moul]

Fixing this:

Related with #1139

[codecov]

Codecov Report

Merging #1147 (6e96574) into master (b7bf42a) will decrease coverage by 4.79%.
The diff coverage is n/a.

❗ Current head 6e96574 differs from pull request most recent head 9a955e4. Consider uploading reports for the commit 9a955e4 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1147      +/-   ##
==========================================
- Coverage   46.97%   42.19%   -4.79%     
==========================================
  Files         364       11     -353     
  Lines       61148     1050   -60098     
==========================================
- Hits        28722      443   -28279     
+ Misses      30061      590   -29471     
+ Partials     2365       17    -2348     

Flag	Coverage Δ
gno.land-_test.gnokey	0.00% <ø> (∅)
gno.land-_test.gnoland	88.14% <ø> (ø)
gno.land-_test.pkgs	27.88% <ø> (ø)
gnovm-_test.cmd	?
gnovm-_test.gnolang.native	?
gnovm-_test.gnolang.other	?
gnovm-_test.gnolang.pkg0	?
gnovm-_test.gnolang.pkg1	?
gnovm-_test.gnolang.pkg2	?
gnovm-_test.gnolang.realm	?
gnovm-_test.gnolang.stdlibs	?
gnovm-_test.pkg	?
tm2-_test.pkg.amino	?
tm2-_test.pkg.bft	?
tm2-_test.pkg.others	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
tm2	∅ <ø> (∅)
gnovm	∅ <ø> (∅)
gno.land	42.19% <ø> (-0.33%)	⬇️

[moul]

This code coverage decrease is probably correct, because we've new files with untested lines. So, maybe your last edit @ajnavarro #1146 is maybe good!