ntdll: Merge the thread data and thread regs structure, and make sure i386 regs are not available on other platforms.

kernel32: Also accept STATUS_BUFFER_OVERFLOW as a valid return code in GetFileInformationByHandle().

FileAllInformation is supposed to also return the file name. If it did,
"all_info" would be too small for the returned data, but since it would still
return as much information as fits in the buffer, we don't need a larger
buffer either.

Otherwise we get the syswow64 directory instead on 64-bit Windows.

This patch fixes a test failure if a user has a non-standard icon size 
set. Windows 7, for instance, offers more variation than previous 
versions of Windows in icon scaling. We should get the system icon 
metric and compare our icon size against that.

The test passes on windows using AMD and Nvidia but not on AMD on
linux. A close look at the spec shows that behavior of a version lower
than 3.0 is up to the driver.

opengl32: No display driver supports windowless opengl3 rendering and likely no driver will ever will.