Keyboard input drop on Windows build

[saschanaz]

Repro:

1. Type github.com/servo/servo on the address bar
2. Expected the exact string but found github.com/serv/serv

I know this is an old known bug but I couldn't find a separate GitHub issue for this.

[elahn]

Confirmed on Windows 10.0.14393 x64.

[BladeMight]

Yes, I have that too on Win7x64.

[atouchet]

This may be the same issue as #13366.

[elahn]

@atouchet that issue describes #12937, but this issue may also be involved in some cases.

[saschanaz]

This issue does not repro on today's build.

[jdm]

Thanks!