Set torusfactor attribute

[paemurru]

Blowing up along a ray does not change whether the toric variety has torus factors.

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 84.37%. Comparing base (5aec608) to head (5beee62).
Report is 10 commits behind head on master.

Files with missing lines	Patch %	Lines
experimental/Schemes/src/ToricBlowups/types.jl	75.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4385   +/-   ##
=======================================
  Coverage   84.36%   84.37%           
=======================================
  Files         656      656           
  Lines       87209    87206    -3     
=======================================
+ Hits        73573    73578    +5     
+ Misses      13636    13628    -8     

Files with missing lines	Coverage Δ
experimental/Schemes/src/ToricBlowups/types.jl	72.13% <75.00%> (+0.20%)	⬆️

... and 10 files with indirect coverage changes

[afkafkafk13]

Is this attribute used (in particular: set and tested) somewhere? This is at least not obvious from this PR.

[paemurru]

It looks like there is one test for blowup of projective 2-space in test/AlgebraicGeometry/ToricVarieties/toric_blowups.jl that also tests for has_torusfactor.