Update Turing src in tests

[mohamed82008]

This PR syncs Turing with the DPPL tests version of Turing. This is helpful because locally I like to develop both Turing and DPPL simultaneously calling using Turing instead of using .Turing in the DPPL tests and then at the end I copy and paste the Turing src to the test folder.

[codecov]

Codecov Report

Merging #114 into master will decrease coverage by 0.24%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #114      +/-   ##
==========================================
- Coverage   75.08%   74.83%   -0.25%     
==========================================
  Files          14       14              
  Lines         907      906       -1     
==========================================
- Hits          681      678       -3     
- Misses        226      228       +2     

Impacted Files	Coverage Δ
src/varinfo.jl	83.38% <0.00%> (-0.62%)	⬇️
src/prob_macro.jl	92.38% <0.00%> (-0.08%)	⬇️

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