add ut for model compression

[denghuilu]

changes

• add ut for model compression
• fix bugs of model compression

[codecov-commenter]

Codecov Report

Merging #586 (f06e8ab) into devel (850169f) will increase coverage by 11.74%.
The diff coverage is 84.21%.

@@             Coverage Diff             @@
##            devel     #586       +/-   ##
===========================================
+ Coverage   62.82%   74.57%   +11.74%     
===========================================
  Files          75       75               
  Lines        6333     6348       +15     
===========================================
+ Hits         3979     4734      +755     
+ Misses       2354     1614      -740     

Impacted Files	Coverage Δ
deepmd/fit/ener.py	94.32% <ø> (+1.03%)	⬆️
deepmd/utils/tabulate.py	88.69% <50.00%> (+72.83%)	⬆️
deepmd/descriptor/se_a.py	97.11% <100.00%> (+6.53%)	⬆️
deepmd/entrypoints/compress.py	97.22% <100.00%> (+62.93%)	⬆️
deepmd/utils/argcheck.py	88.02% <100.00%> (+71.66%)	⬆️
deepmd/utils/data.py	91.32% <0.00%> (+0.68%)	⬆️
deepmd/common.py	83.08% <0.00%> (+2.94%)	⬆️
deepmd/utils/data_system.py	71.28% <0.00%> (+3.21%)	⬆️
deepmd/utils/compat.py	83.33% <0.00%> (+5.55%)	⬆️
... and 15 more

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