ci: fix test step.

The flags were switched. tapfiles should use -j to run tests in
parallel, test-results should use -s so only the actual test results
show up on screen.

.github/workflows/build.yml

@@ -32,4 +32,4 @@ jobs:
  - name: Build IOC
  run: make -j$(nproc)
  - name: Run tests
- run: make -s tapfiles && make test-results
+ run: make -j tapfiles && make -s test-results