[PATCH] gdiplus: Disable PNG encoding filters.

[Florian Will]

There is a Testbot failure for "32 bit Chinese:China" for my patch,
but it seems unrelated to my change? The failing test is in font.c,
line 888:

    status = GdipCreateFontFamilyFromName(L"MS Shell Dlg", NULL, &family);
    expect(Ok, status);

where status is 14, FontFamilyNotFound. Hopefully this is not some
hidden issue with my code, like corrupting some memory?