test-docs-build: Use fast runner

Author: KrystalDelusion

.github/workflows/test-build.yml

@@ -192,7 +192,7 @@ jobs:
 
   test-docs-build:
     name: Try build docs
-    runs-on: [self-hosted, linux, x64]
+    runs-on: [self-hosted, linux, x64, fast]
     needs: [pre_docs_job]
     if: needs.pre_docs_job.outputs.should_skip != 'true'
     strategy: