Debuginfo tests spurious failures on MinGW #40835
Description
Hangs forever
- https://ci.appveyor.com/project/rust-lang/rust/build/1.0.2565/job/scag42v11o50nymd
- https://ci.appveyor.com/project/rust-lang/rust/build/1.0.2561/job/6rc6qx2aqfrev0xc
Likely #40777 (or at least, the part of it that is a fix to #40184).