Fix github CI (#1778)

Summary:
Pull Request resolved: #1778

All tests are currently breaking due to a mismatch between `/lib64/libstdc++.so.6` (linked at runtime) and `${CONDA_PREFIX}/lib/libstdc++.so.6` (use during compilation) when trying to import `_rust_bindings.so`. We can fix this at least for now by setting `LD_PRELOAD` to point to the conda env's `libstdc++.so.6` before running the tests.

Reviewed By: zdevito

Differential Revision: D86577656

fbshipit-source-id: d600efe909d837b7983462caa526ec31aa465ff9

Author: samlurye

scripts/common-setup.sh

@@ -169,6 +169,12 @@ run_test_groups() {
     echo "Usage: run_test_groups <enable_actor_error_test: 0|1>"
     return 2
   fi
+  # Make sure the runtime linker uses the conda env's libstdc++
+  # (which was used to compile monarch) instead of the system's.
+  # TODO: Revisit this to determine if this is the proper/most
+  # sustainable/most robust solution.
+  export CONDA_LIBSTDCPP="${CONDA_PREFIX}/lib/libstdc++.so.6"
+  export LD_PRELOAD="${CONDA_LIBSTDCPP}${LD_PRELOAD:+:$LD_PRELOAD}"
   local FAILED_GROUPS=()
   for GROUP in $(seq 1 10); do
     echo "Running test group $GROUP of 10..."