test-build.yml Use pre_docs_job for build-yosys

pre_job will never skip something that is not skipped by pre_docs_job, so we can gate the build step by pre_docs_job to skip it when the two later jobs are both being skipped.

.github/workflows/test-build.yml

@@ -33,6 +33,8 @@ jobs:
   build-yosys:
     name: Reusable build
     runs-on: ${{ matrix.os }}
+    needs: pre_docs_job
+    if: needs.pre_docs_job.outputs.should_skip != 'true'
     env:
       CC: clang
     strategy: