x86_64 self-hosted backend behavior tests are failing on Windows

[andrewrk]

Zig Version: 0.11.0-dev.2634+b0186f310

I apologize for misplacing the CI error logs for this bug report, but one can observe them by opening a pull request with these lines deleted:

zig/test/tests.zig

Lines 945 to 951 in b0186f3

	// TODO get the x86_64 self-hosted backend tests passing on Windows
	if (test_target.target.getCpuArch() == .x86_64 and
	test_target.target.getOsTag() == .windows and
	test_target.use_llvm == false)
	{
	continue;
	}

Until this issue is resolved, the CI does not provide test coverage for the x86_64 self-hosted backend on Windows.

[jacobly0]

Reenabled in #15302 on the off chance that it fixes the issue, otherwise will investigate further.