mongotest core dumps when the .results file for a test does not exist. It should exit with code 1, but not leave a core behind.

You can see this behavior in the self-test: src/mongo/db/query/query_tester/tests/selfTests/test_no_matching_res.py 
(remove the with discard_coredumps() context manager if present)

$ bazel build install-dist-test
$ bazel run //buildscripts:resmoke – run --suite query_tester_self_test src/mongo/db/query/query_tester/tests/selfTests/test_no_matching_res.py

See dump_mongotest.12345.core in working directory