investigate flaky test-worker-terminate-http2-respond-with-file

Haven't seen this one before. Worth further investigation?

https://ci.nodejs.org/job/node-test-commit-linuxone/17161/nodes=rhel72-s390x/console

test-linuxonecc-rhel72-s390x-2

00:05:40 not ok 2360 parallel/test-worker-terminate-http2-respond-with-file
00:05:40   ---
00:05:40   duration_ms: 0.729
00:05:40   severity: crashed
00:05:40   exitcode: -6
00:05:40   stack: |-
00:05:40     out/Release/node[53404]: ../src/env.cc:435:virtual node::Environment::~Environment(): Assertion `(base_object_count()) == (0)' failed.
00:05:40      1: 0x805f36ec node::Abort() [out/Release/node]
00:05:40      2: 0x805f377c  [out/Release/node]
00:05:40      3: 0x80593306 node::Environment::~Environment() [out/Release/node]
00:05:40      4: 0x805936d2 node::Environment::~Environment() [out/Release/node]
00:05:40      5: 0x8068fe3c node::worker::Worker::Run() [out/Release/node]
00:05:40      6: 0x8069008c  [out/Release/node]
00:05:40      7: 0x3ff8888825a  [/lib64/libpthread.so.0]
00:05:40      8: 0x3ff8878dcf2  [/lib64/libc.so.6]
00:05:40   ...

@nodejs/workers @nodejs/http2 @nodejs/testing