workflows: make more builds mandatory: check_generated_code, ...

...`docker_image_amd64`, and `examples_orms`

Epic: CRDB-8308
Release note: None

.github/bors.toml

@@ -4,6 +4,9 @@
 # pushed to master.
 status = [
        "Bazel Essential CI (Cockroach)",
+       "check_generated_code",
+       "docker_image_amd64",
+       "examples_orms",
        "macos_amd64_build",
        "macos_arm64_build",
        "windows_build",

.github/workflows/github-actions-essential-ci.yml

@@ -50,7 +50,7 @@ jobs:
       - name: clean up
         run: ./build/github/cleanup-engflow-keys.sh
         if: always()
-  EXPERIMENTAL_check_generated_code:
+  check_generated_code:
     runs-on: [self-hosted, basic_runner_group]
     steps:
       - uses: actions/checkout@v4
@@ -64,7 +64,7 @@ jobs:
       - name: clean up
         run: ./build/github/cleanup-engflow-keys.sh
         if: always()
-  EXPERIMENTAL_docker_image_amd64:
+  docker_image_amd64:
     runs-on: [self-hosted, basic_runner_group]
     steps:
       - uses: actions/checkout@v4
@@ -82,7 +82,7 @@ jobs:
       - name: clean up
         run: ./build/github/cleanup-engflow-keys.sh
         if: always()
-  EXPERIMENTAL_examples_orms:
+  examples_orms:
     runs-on: [self-hosted, basic_big_runner_group_fips]
     steps:
       - uses: actions/checkout@v4