ole32/tests: Show that it's the loword of the separate flag parameter that determines the marshalling context.

wgl: Make sure WGL_SUPPORT_GDI_ARB is only seen on formats on which we set it during startup (in get_formats).

urlmon: Added BINDSTATUS_LOADINGMIMEHANDLER and BINDSTATUS_LOADINGMIMEHANDLER support to Binding object.

winetest: Rename xmalloc() & co to heap_xxx() to not imply they are based on malloc(), and add heap_free().

oleaut32: Add a failing VarFormat test showing that wine wrongly truncates decimals with large negative exponents instead of rounding.

Fixes a memory leak on an error path. Found by Smatch.