Bug 702245: Don't mark Separation as visited before loading it.
Bug 702245: Don't mark Separation as visited before loading it.

Separation colorspaces are never recursed in find_seps, but they
are loaded. The loading checks if the colorspace has been visited,
which would bail early and refuse to load. Move the marking logic
into the Indexed and DeviceN cases where it is needed.

ArtifexSoftware/mupdf,TamirEvan/mupdf,ccxvii/mupdf,TamirEvan/mupdf,sebras/mupdf,sebras/mupdf,TamirEvan/mupdf,sebras/mupdf,ccxvii/mupdf,ArtifexSoftware/mupdf,ccxvii/mupdf,ArtifexSoftware/mupdf,ccxvii/mupdf,ArtifexSoftware/mupdf,sebras/mupdf,ArtifexSoftware/mupdf,ccxvii/mupdf,sebras/mupdf,TamirEvan/mupdf,TamirEvan/mupdf,TamirEvan/mupdf,ArtifexSoftware/mupdf,ArtifexSoftware/mupdf,ccxvii/mupdf,ArtifexSoftware/mupdf,TamirEvan/mupdf,TamirEvan/mupdf,sebras/mupdf