ci: disable alt build during try builds

The build is not actually needed often, and it can be added back on a
case-by-case basis if a specific PR needs access to it.

.github/workflows/ci.yml

@@ -152,10 +152,6 @@ jobs:
           - name: dist-x86_64-linux
             os: ubuntu-latest-xl
             env: {}
-          - name: dist-x86_64-linux-alt
-            env:
-              IMAGE: dist-x86_64-linux
-            os: ubuntu-latest-xl
     timeout-minutes: 600
     runs-on: "${{ matrix.os }}"
     steps:

src/ci/azure-pipelines/try.yml

@@ -26,8 +26,6 @@ jobs:
   strategy:
     matrix:
       dist-x86_64-linux: {}
-      dist-x86_64-linux-alt:
-        IMAGE: dist-x86_64-linux
 
 # The macOS and Windows builds here are currently disabled due to them not being
 # overly necessary on `try` builds. We also don't actually have anything that

src/ci/github-actions/ci.yml

@@ -281,11 +281,6 @@ jobs:
           - name: dist-x86_64-linux
             <<: *job-linux-xl
 
-          - name: dist-x86_64-linux-alt
-            env:
-              IMAGE: dist-x86_64-linux
-            <<: *job-linux-xl
-
   auto:
     <<: *base-ci-job
     name: auto