Run only fuzztest tests in fuzztest workflow

.github/workflows/ci-linux-shared-local-fuzztest.yml

@@ -1,4 +1,7 @@
-# Builds libavif with local aom and dav1d and runs tests including fuzztest.
+# Builds libavif with local aom and dav1d and runs fuzztest tests
+# (tests that have 'fuzztest' in their name).
+# They are run in "unit test mode" (run with random inputs for a short period of time)
+# see https://github.com/google/fuzztest/blob/main/doc/quickstart-cmake.md
 # Runs on ubuntu only. libavif is built with clang.
 
 name: CI Unix Shared Local Fuzztest
@@ -63,6 +66,6 @@ jobs:
     - name: Build libavif (ninja)
       working-directory: ./build
       run: ninja
-    - name: Run AVIF Tests
+    - name: Run fuzztest AVIF Tests
       working-directory: ./build
-      run: ctest -j $(getconf _NPROCESSORS_ONLN) --output-on-failure
+      run: ctest -j $(getconf _NPROCESSORS_ONLN) --output-on-failure -R fuzztest