winedump, dbghelp: In .pdb files (>= VC2005), handle the case where the codeview_linetab2_file structure is not the first one.

winex11: Make sure the formats are the same instead of the depths since the bit ordering can be different.

The internal order of the depth and stencil bits is unspecified since the
format isn't lockable.

We don't just use the function for StorageImpl.