Revert "Disable pre-5.5 versions in the format compatibility test (#5990)" (#5999)

Summary:
This reverts commit 351e2540.

All branches have been fixed to buildable on FB environments, so we can revert it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5999

Differential Revision: D18281947

fbshipit-source-id: 6deaaf1b5df2349eee5d6ed9b91208cd7e23ec8e

tools/check_format_compatible.sh

@@ -53,13 +53,10 @@ with open('${sorted_input_data}', 'w') as f:
     print >> f, k + " ==> " + v
 EOF
 
-# Disable pre-5.5 versions that have not been ported to gcc7.
-#declare -a backward_compatible_checkout_objs=("2.2.fb.branch" "2.3.fb.branch" "2.4.fb.branch" "2.5.fb.branch" "2.6.fb.branch" "2.7.fb.branch" "2.8.1.fb" "3.0.fb.branch" "3.1.fb" "3.2.fb" "3.3.fb" "3.4.fb" "3.5.fb" "3.6.fb" "3.7.fb" "3.8.fb" "3.9.fb")
-#declare -a forward_compatible_checkout_objs=("3.10.fb" "3.11.fb" "3.12.fb" "3.13.fb" "4.0.fb" "4.1.fb" "4.2.fb" "4.3.fb" "4.4.fb" "4.5.fb" "4.6.fb" "4.7.fb" "4.8.fb" "4.9.fb" "4.10.fb" "4.11.fb" "4.12.fb" "4.13.fb" "5.0.fb" "5.1.fb" "5.2.fb" "5.3.fb" "5.4.fb" "5.5.fb" "5.6.fb" "5.7.fb" "5.8.fb" "5.9.fb" "5.10.fb")
-declare -a forward_compatible_checkout_objs=("5.5.fb" "5.6.fb" "5.7.fb" "5.8.fb" "5.9.fb" "5.10.fb")
+declare -a backward_compatible_checkout_objs=("2.2.fb.branch" "2.3.fb.branch" "2.4.fb.branch" "2.5.fb.branch" "2.6.fb.branch" "2.7.fb.branch" "2.8.1.fb" "3.0.fb.branch" "3.1.fb" "3.2.fb" "3.3.fb" "3.4.fb" "3.5.fb" "3.6.fb" "3.7.fb" "3.8.fb" "3.9.fb")
+declare -a forward_compatible_checkout_objs=("3.10.fb" "3.11.fb" "3.12.fb" "3.13.fb" "4.0.fb" "4.1.fb" "4.2.fb" "4.3.fb" "4.4.fb" "4.5.fb" "4.6.fb" "4.7.fb" "4.8.fb" "4.9.fb" "4.10.fb" "4.11.fb" "4.12.fb" "4.13.fb" "5.0.fb" "5.1.fb" "5.2.fb" "5.3.fb" "5.4.fb" "5.5.fb" "5.6.fb" "5.7.fb" "5.8.fb" "5.9.fb" "5.10.fb")
 declare -a forward_compatible_with_options_checkout_objs=("5.11.fb" "5.12.fb" "5.13.fb" "5.14.fb" "5.15.fb" "5.16.fb" "5.17.fb" "5.18.fb" "6.0.fb" "6.1.fb" "6.2.fb" "6.3.fb" "6.4.fb" "6.5.fb")
-#declare -a checkout_objs=(${backward_compatible_checkout_objs[@]} ${forward_compatible_checkout_objs[@]} ${forward_compatible_with_options_checkout_objs[@]})
-declare -a checkout_objs=(${forward_compatible_checkout_objs[@]} ${forward_compatible_with_options_checkout_objs[@]})
+declare -a checkout_objs=(${backward_compatible_checkout_objs[@]} ${forward_compatible_checkout_objs[@]} ${forward_compatible_with_options_checkout_objs[@]})
 declare -a extern_sst_ingestion_compatible_checkout_objs=("5.14.fb" "5.15.fb" "5.16.fb" "5.17.fb" "5.18.fb" "6.0.fb" "6.1.fb" "6.2.fb" "6.3.fb" "6.4.fb" "6.5.fb")
 
 generate_db()