Split coverage and unit tests

[AmintorDusko]

Context: Building coverage tests in Debug mode for CodeCov.

Description of the Change: Split unit and coverage test to build coverage tests in debug mode.

Benefits: CodeCov will work properly.

Possible Drawbacks:

Related GitHub Issues:

[github-actions]

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Please edit .github/CHANGELOG.md with:

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[codecov]

Codecov Report

Merging #359 (ae7446a) into master (08831c1) will increase coverage by 1.48%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #359      +/-   ##
==========================================
+ Coverage   98.39%   99.88%   +1.48%     
==========================================
  Files          49       49              
  Lines        4163     4184      +21     
==========================================
+ Hits         4096     4179      +83     
+ Misses         67        5      -62     

Impacted Files	Coverage Δ
pennylane_lightning/_version.py	100.00% <100.00%> (ø)
pennylane_lightning/src/simulator/Measures.hpp	99.37% <0.00%> (-0.63%)	⬇️
pennylane_lightning/src/util/Memory.hpp	100.00% <0.00%> (ø)
pennylane_lightning/src/util/BitUtil.hpp	100.00% <0.00%> (ø)
pennylane_lightning/src/util/RuntimeInfo.cpp	100.00% <0.00%> (ø)
pennylane_lightning/src/util/ConstantUtil.hpp	100.00% <0.00%> (ø)
pennylane_lightning/src/util/LinearAlgebra.hpp	100.00% <0.00%> (ø)
pennylane_lightning/src/util/IntegerInterval.hpp	100.00% <0.00%> (ø)
...ennylane_lightning/src/gates/DynamicDispatcher.hpp	100.00% <0.00%> (ø)
...nylane_lightning/src/gates/RegisterKernels_x64.cpp	100.00% <0.00%> (ø)
... and 5 more

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[chaeyeunpark]

Thanks for a quick fix @AmintorDusko !

[mlxd]

Thanks @AmintorDusko