ci: Pass full env to CI pod to avoid missing a var

Instead of enumerating each passed env var, just pass all. This avoids
the risk of missing to enumerate one. Also, it is less code.

The risk could be that an env var causes non-deterministic behavior, but
this can be fixed by explicitly excluding it once the issue is known.

Values with newlines can not be stored in the file and parsed by
docker/podman, so they are excluded.

ci/README.md

@@ -14,10 +14,10 @@ testing compared to other parts of the codebase. If you want to keep the work tr
 system in a virtual machine with a Linux operating system of your choice.
 
 To allow for a wide range of tested environments, but also ensure reproducibility to some extent, the test stage
-requires `docker` to be installed. To install all requirements on Ubuntu, run
+requires `bash`, `docker`, and `python3` to be installed. To install all requirements on Ubuntu, run
 
 ```
-sudo apt install docker.io bash
+sudo apt install bash docker.io python3
 ```
 
 To run the default test stage,

ci/test/04_install.sh

@@ -18,7 +18,6 @@ export ASAN_OPTIONS="detect_stack_use_after_return=1:check_initialization_order=
 export LSAN_OPTIONS="suppressions=${BASE_ROOT_DIR}/test/sanitizer_suppressions/lsan"
 export TSAN_OPTIONS="suppressions=${BASE_ROOT_DIR}/test/sanitizer_suppressions/tsan:halt_on_error=1:log_path=${BASE_SCRATCH_DIR}/sanitizer-output/tsan"
 export UBSAN_OPTIONS="suppressions=${BASE_ROOT_DIR}/test/sanitizer_suppressions/ubsan:print_stacktrace=1:halt_on_error=1:report_error_type=1"
-env | grep -E '^(BITCOIN_CONFIG|BASE_|QEMU_|CCACHE_|LC_ALL|BOOST_TEST_RANDOM|DEBIAN_FRONTEND|CONFIG_SHELL|(ASAN|LSAN|TSAN|UBSAN)_OPTIONS|PREVIOUS_RELEASES_DIR)' | tee /tmp/env
 if [[ $BITCOIN_CONFIG = *--with-sanitizers=*address* ]]; then # If ran with (ASan + LSan), Docker needs access to ptrace (https://github.com/google/sanitizers/issues/764)
   CI_CONTAINER_CAP="--cap-add SYS_PTRACE"
 fi
@@ -27,6 +26,9 @@ export P_CI_DIR="$PWD"
 export BINS_SCRATCH_DIR="${BASE_SCRATCH_DIR}/bins/"
 
 if [ -z "$DANGER_RUN_CI_ON_HOST" ]; then
+  # Export all env vars to avoid missing some.
+  # Though, exclude those with newlines to avoid parsing problems.
+  python3 -c 'import os; [print(f"{key}={value}") for key, value in os.environ.items() if "\n" not in value]' | tee /tmp/env
   echo "Creating $CI_IMAGE_NAME_TAG container to run in"
   DOCKER_BUILDKIT=1 ${CI_RETRY_EXE} docker build \
       --file "${BASE_ROOT_DIR}/ci/test_imagefile" \