Don't always set SUDO.

Rely on sourcing configs to set as appropriate.

.github/workflows/c-cpp.yml

@@ -52,7 +52,6 @@ jobs:
     - name: make tests
       run: ./.github/run_test.sh ${{ matrix.configs }}
       env:
-        SUDO: sudo
         TEST_SSH_UNSAFE_PERMISSIONS: 1
     - name: save logs
       if: failure()

.github/workflows/selfhosted.yml

@@ -10,7 +10,6 @@ jobs:
     runs-on: ${{ matrix.os }}
     env:
       TARGET_HOST: ${{ matrix.os }}
-      SUDO: sudo
     strategy:
       fail-fast: false
       # We use a matrix in two parts: firstly all of the VMs are tested with the