[release-23.0] CI: Improve reliability of codecov workflow with larger runner (vitessio#18992) (vitessio#18995)

Signed-off-by: Matt Lord <mattalord@gmail.com>
Co-authored-by: vitess-bot[bot] <108069721+vitess-bot[bot]@users.noreply.github.com>
Signed-off-by: Jun Wang <jun.wang@demonware.net>

Author: vitess-bot[bot]

.github/workflows/codecov.yml

@@ -16,7 +16,7 @@ permissions: read-all
 jobs:
   test:
     name: Code Coverage
-    runs-on: ubuntu-24.04
+    runs-on: oracle-vm-8cpu-32gb-x86-64
 
     steps:
     - name: Check out code