Spurious failure in test_process_output_fail_to_start

[alexcrichton]

First seen at #43271 (comment) logs are https://travis-ci.org/rust-lang/rust/jobs/254360556 and ends with:

[01:11:23] test process::tests::test_add_to_env ... ok
[01:11:23] test process::tests::test_finish_once ... ignored
[01:11:23] test process::tests::test_finish_twice ... ignored
[01:11:23] test process::tests::test_inherit_env ... ok
[01:11:23] test process::tests::test_interior_nul_in_arg_is_error ... ok
[01:11:23] test process::tests::test_interior_nul_in_args_is_error ... ok
[01:11:23] test process::tests::test_interior_nul_in_current_dir_is_error ... ok
[01:11:23] test process::tests::test_interior_nul_in_env_key_is_error ... ok
[01:11:23] test process::tests::test_interior_nul_in_env_value_is_error ... ok
[01:11:23] test process::tests::test_interior_nul_in_progname_is_error ... ok
[01:11:23] test process::tests::test_override_env ... ok
[01:11:23] test process::tests::test_process_output_error ... ignored
[01:12:23] test process::tests::test_process_output_fail_to_start ... test process::tests::test_process_output_fail_to_start has been running for over 60 seconds


No output has been received in the last 30m0s, this potentially indicates a stalled build or something wrong with the build itself.
Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received

The build has been terminated

Note that this is in QEMU emulation, so there could just be something funky going on there...