Improve stat performance on Windows

[wolfs]

The PR #37 switched from using GetFileAttributesExW to GetFileInformationByHandle for symlink support. This seems to be much slower.

The same issue seems to have appeared in Visual Studio: dotnet/msbuild#2052

There, they fixed this in dotnet/msbuild#2087 by first calling GetFileAttributesExW, and then falling back to use GetFileInformationByHandle only if the target is actually a symlink.

The JMH benchmark in the native subproject of gradle/gradle shows the difference:

Latest native platform, Windows 10 (from gradle/gradle#12966 (comment)):

Old benchmark result from 2017 (from gradle/gradle#1183 (comment)):

Java NIO seems to be using GetFileAttributesW, and I think that is the only explanation for the much higher performance.