Fix CI to run the unit tests without optional deps (#11017)

This also turns off calculating code coverage, as we didn't use it and it was a lot of noise

.github/workflows/tests.yml

@@ -78,20 +78,23 @@ jobs:
       matrix:
         python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
         database: ["sqlite"]
+        toxenv: ["py"]
         include:
           # Newest Python without optional deps
           - python-version: "3.10"
-            toxenv: "py-noextras,combine"
+            toxenv: "py-noextras"
 
           # Oldest Python with PostgreSQL
           - python-version: "3.6"
             database: "postgres"
             postgres-version: "9.6"
+            toxenv: "py"
 
           # Newest Python with newest PostgreSQL
           - python-version: "3.10"
             database: "postgres"
             postgres-version: "14"
+            toxenv: "py"
 
     steps:
       - uses: actions/checkout@v2
@@ -111,7 +114,7 @@ jobs:
         if: ${{ matrix.postgres-version }}
         timeout-minutes: 2
         run: until pg_isready -h localhost; do sleep 1; done
-      - run: tox -e py,combine
+      - run: tox -e ${{ matrix.toxenv }}
         env:
           TRIAL_FLAGS: "--jobs=2"
           SYNAPSE_POSTGRES: ${{ matrix.database == 'postgres' || '' }}
@@ -169,7 +172,7 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
       - run: pip install tox
-      - run: tox -e py,combine
+      - run: tox -e py
         env:
           TRIAL_FLAGS: "--jobs=2"
       - name: Dump logs