ngine traceback:
  in select
  in pants.core.goals.test.run_tests
  in pants.core.goals.test.enrich_test_result (src/python/pants/help/list_goals_integration_test.py:integration)
  in pants.backend.python.goals.pytest_runner.run_python_test (src/python/pants/help/list_goals_integration_test.py:integration)
  in pants.backend.python.goals.pytest_runner.setup_pytest_for_target
  in pants.backend.python.util_rules.pex.create_pex
  in pants.backend.python.util_rules.pex.find_interpreter (CPython==3.6.*)
  in pants.backend.python.util_rules.pex_cli.setup_pex_cli_process
  in pants.core.util_rules.external_tool.download_external_tool
  in downloaded_file
Traceback (no traceback):
  <pants native internals>
Exception: Server error (500) downloading file pex from <https://github.com/pantsbuild/pex/releases/download/v2.1.19/pex>
*** Error in `python3.6 ./pants.pex test build-support:: src:: tests:: pants-plugins::1': double free or corruption (fasttop)7: 0x00007f6e9cb36b40 ***
======= Backtrace: =========
:/lib/x86_64-linux-gnu/libc.so.6(+0x777f505:56.2/lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x9/home/travis/.pex/code/c490c036c0d370c726fe47a5472a342f575968f7/pants/engine/internals/native_engine.so ([+0xW12cdc0)[0x7f6ead024dc0]
/home/travis/.pex/code/c490c036c0d370c726fe47a5472a342f575968f7/pants/engine/internals/native_engine.so(+0x20f1e7)[0x7f6ead1071e7]
/home/travis/.pex/code/c490c036c0d370c726fe47a5472a342f575968f7/pants/engine/internals/native_engine.so(+0x2261b0)[0x7f6ead11e1b0]
/home/travis/.pex/code/c490c036c0d370c726fe47a5472a342f575968f7/pants/engine/internals/native_engine.so(+0x2c4ab7)[0x7f6ead1bcab7]
/home/travis/.pex/code/c490c036c0d370c726fe47a5472a342f575968f7/pants/engine/internals/native_engine.so(+0x1fc5d2)[0x7f6ead0f45d2]
/home/travis/.pex/code/c490c036c0d370c726fe47a5472a342f575968f7/pants/engine/internals/native_engine.so(+0x119976)[0x7f6ead011976]
...