wined3d: Write into a mapped BO when replacing the entire destination in wined3d_context_gl_copy_bo_address().

Instead of using glBufferSubData(). In practice, this means that we will either
discard and rename the BO (if it's still in use) or write directly into it (if
not).

This improves performance drastically on NVidia GL drivers.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=53408