`cargo test` in CI is crashing on Windows with no information

[dtolnay]

I noticed the same failure on PRs #652, #654, #655.

Something is silently crashing the test harness after running only 23 of the 31 tests in tests/test.rs.

running 31 tests
test gnu_debug_fp ... ok
test gnu_compile_assembly ... ok
test gnu_debug_fp_auto ... ok
test gnu_define ... ok
test gnu_debug_nofp ... ok
test gnu_extra_warnings0 ... ok
test gnu_flag_if_supported ... ok
test gnu_flag_if_supported_cpp ... ok
test gnu_extra_warnings1 ... ok
test gnu_i686 ... ok
test gnu_i686_pic ... ok
test gnu_include ... ok
test gnu_opt_level_1 ... ok
test gnu_opt_level_s ... ok
test gnu_set_stdlib ... ok
test gnu_shared ... ok
test gnu_smoke ... ok
test gnu_static ... ok
test gnu_warnings ... ok
test gnu_warnings_into_errors ... ok
test gnu_warnings_overridable ... ok
test gnu_x86_64 ... ok
test gnu_x86_64_no_pic ... ok
error: test failed, to rerun pass '--test test'
Error: Process completed with exit code 1.

[dot-asm]

This was resolved and can be closed.