chore(ci) fix large CI workflow file

Although the workflow has been testing successfully all supported
builds, it has been failing due to a single-entry bracket-list that
Github seems particularly sensitive towards.

.github/workflows/ci-large.yml

@@ -130,7 +130,6 @@ jobs:
       fail-fast: false
       matrix:
         label: [""]
-        os: [ubuntu-latest]
         cc: [clang-13, clang-14, gcc-10, gcc-11]
         ngx: [1.25.3]
         runtime: [wasmtime, wasmer, v8]
@@ -139,14 +138,13 @@ jobs:
         v8: [11.4.183.23]
         include:
           - label: old_nginx
-            os: [ubuntu-latest]
             cc: clang-15
             ngx: 1.21.6
             runtime: wasmtime
             wasmtime: 14.0.3
     uses: ./.github/workflows/job-build-tests.yml
     with:
-      os: ${{ matrix.os }}
+      os: ubuntu-latest
       cc: ${{ matrix.cc }}
       ngx: ${{ matrix.ngx }}
       runtime: ${{ matrix.runtime }}