Test failures on pc-windows-gnu

[dtolnay]

As of the most recent nightly, rustc 1.42.0-nightly (01a46509a 2019-12-20), our Windows builder in Travis has begun failing. https://travis-ci.com/dtolnay/linkme/jobs/269503401

Both cargo test and cargo test --release fail on Windows with the following:

thread 'test' panicked at 'assertion failed: `(left == right)`
  left: `0`,
 right: `3`', tests\distributed_slice.rs:17:5

The relevant code in the test file is:

linkme/tests/distributed_slice.rs

Lines 3 to 17 in 5376b49

	#[distributed_slice]
	static SHENANIGANS: [i32] = [..];
	#[distributed_slice(SHENANIGANS)]
	static N: i32 = 9;
	#[distributed_slice(SHENANIGANS)]
	static NN: i32 = 99;
	#[distributed_slice(SHENANIGANS)]
	static NNN: i32 = 999;
	#[test]
	fn test() {
	assert_eq!(SHENANIGANS.len(), 3);

Mentioning @kabergstrom in case this is something you might be able to look into.

[dtolnay]

pc-windows-msvc does not appear to be affected.