Integrate monolithic build into coverage test

This addresses an issue where a subclass relationship not explicitly
noted in the profile graph gets missed when reviewing whether a
higher-level concept has been tested.

E.g. when reviewing the Endurant vs Perdurant proposal (UCO Issue 544),
had the following statements:

Profile graph:

```turtle
uco-core:Item
	rdfs:subClassOf drafting:Endurant ;
	.
```

Exemplars graph:

```turtle
kb:File-e364d7d2-25c8-4d4a-95d1-b03f73934e83
	a uco-observable:File ;
	.
```

Upstream, UCO contains subclass statements that tie `uco-observable:File`
to `uco-core:Item`, but the profiles graph did not contain those axioms.
So, the exemplars coverage test failed, reporting that `core:Item` had
not been demonstrated.

After this patch, exemplars coverage now respects all imported subclass
hierarchies.

References:
* ucoProject/UCO#544

Signed-off-by: Alex Nelson <alexander.nelson@nist.gov>

tests/Makefile

@@ -39,8 +39,8 @@ all: \
 	touch $@
 
 .pytest.done.log: \
-  $(profile_ttls) \
   exemplars.ttl \
+  monolithic.ttl \
   test_exemplar_coverage.py
 	source $(top_srcdir)/venv/bin/activate \
 	  && pytest \

tests/test_exemplar_coverage.py

@@ -37,6 +37,7 @@ def test_exemplar_coverage() -> None:
     """
     exemplar_graph = Graph()
     profile_graph = Graph()
+    tbox_graph = Graph()
     combined_graph = Graph()
 
     for filepath in (top_srcdir / "ontology").iterdir():
@@ -48,12 +49,15 @@ def test_exemplar_coverage() -> None:
             profile_graph.parse(filepath)
     logging.debug("len(profile_graph) = %d.", len(profile_graph))
 
+    monolithic_filepath = srcdir / "monolithic.ttl"
+    tbox_graph.parse(monolithic_filepath)
+
     exemplar_filepath = srcdir / "exemplars.ttl"
     logging.debug("Loading exemplars graph %r.", exemplar_filepath)
     exemplar_graph.parse(exemplar_filepath)
     logging.debug("len(exemplar_graph) = %d.", len(exemplar_graph))
 
-    combined_graph = exemplar_graph + profile_graph
+    combined_graph = exemplar_graph + tbox_graph
 
     classes_mapped: Set[URIRef] = set()
     classes_with_exemplars: Set[URIRef] = set()