Adding to unity substitution set

[victorli2002]

Filling out unity_substitution_set with tests

---

This change is 

[victorli2002]

Reviewable status: 0 of 437 files reviewed, 1 unresolved discussion

---

lib/substitutions/test/src/substitutions/unity_substitution_set.cc line 34 at r1 (raw file):

  TEST_CASE("create_replicate_linear_combine") {
    SUBCASE("use_bias = false") {

Having trouble getting this test to work, not sure where needs to be fixed.

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 23 lines in your changes missing coverage. Please review.

Project coverage is 64.04%. Comparing base (10ef31b) to head (4fe85ed).

Files with missing lines	Patch %	Lines
...rc/substitutions/sub_parallel_computation_graph.cc	0.00%	19 Missing ⚠️
...utions/src/substitutions/unity_substitution_set.cc	98.58%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1594      +/-   ##
==========================================
+ Coverage   62.90%   64.04%   +1.14%     
==========================================
  Files         635      636       +1     
  Lines       15201    15540     +339     
==========================================
+ Hits         9562     9953     +391     
+ Misses       5639     5587      -52     

Flag	Coverage Δ
unittests	64.04% <93.33%> (+1.14%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
lib/compiler/src/compiler/graph_optimize_result.cc	0.00% <ø> (ø)
...rc/substitutions/operator_pattern/get_attribute.cc	31.54% <100.00%> (+23.62%)	⬆️
...utput_graph/materialize_operator_from_attrs_map.cc	81.25% <100.00%> (+31.25%)	⬆️
...utions/src/substitutions/unity_substitution_set.cc	98.68% <98.58%> (+17.95%)	⬆️
...rc/substitutions/sub_parallel_computation_graph.cc	67.24% <0.00%> (-13.18%)	⬇️

... and 1 file with indirect coverage changes