Do not use multiple variable bounds in copytest

[blegat]

Some solvers do not support that

[codecov-io]

Codecov Report

Merging #521 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #521      +/-   ##
==========================================
+ Coverage   95.59%   95.59%   +<.01%     
==========================================
  Files          46       46              
  Lines        4676     4704      +28     
==========================================
+ Hits         4470     4497      +27     
- Misses        206      207       +1

Impacted Files	Coverage Δ
src/Test/modellike.jl	100% <100%> (ø)	⬆️
src/Bridges/squarepsdbridge.jl	96.42% <0%> (-0.24%)	⬇️
src/Utilities/constraints.jl	100% <0%> (ø)	⬆️

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