BATS in testing can't work with empty test

The test for C & C++ is due to the dependencies the same as with only
C++, duplicating made no sense but commenting why we skip did. The skip
is now explicit so when we can check for compilers besides the GNU ones
we can enable this again.

.github/jobs/configure-checks/all.bats

@@ -129,14 +129,6 @@ compile_assertions_finished () {
     compile_assertions_finished
 }
 
-@test "Install GNU C/C++ compilers" {
-    # The test above already does this
-    # repo-remove clang
-    # repo-install gcc g++ libcgroup-dev
-    # compiler_assertions
-    # compile_assertions_finished
-}
-
 @test "Install C/C++ compilers (Clang as alternative)" {
     if [ "$distro_id" = "ID=fedora" ]; then
         # Fedora has gcc as dependency for clang