Description:
Prior to #7555, we didn't statically link libstdc++ in tests, so the test didn't fail though it is now fails under Ubuntu 18.04 with gperftools HEAPCHECK. Since we do statically link libstdc++ for released envoy binary, I suspect this is the issue living there for a while.

LSAN also detects the leak if we link libstdc++ statically in ASAN build.

Some error logs caught by Bazel CI:
https://storage.googleapis.com/bazel-untrusted-buildkite-artifacts/69421b65-80ea-4551-bcc7-7094f44dbe62/test/extensions/tracers/dynamic_ot/config_test/attempt_1.log
https://storage.googleapis.com/bazel-untrusted-buildkite-artifacts/69421b65-80ea-4551-bcc7-7094f44dbe62/test/extensions/tracers/dynamic_ot/dynamic_opentracing_driver_impl_test/attempt_1.log