Fix simple solidify wrong custom data on large ngons

Fixes an unreported issue that vertex data on large ngons (>255)
is messed up due to type conversion to char and back to int.

Ref D10734

source/blender/modifiers/intern/MOD_solidify_extrude.c

@@ -216,7 +216,7 @@ Mesh *MOD_solidify_extrude_modifyMesh(ModifierData *md, const ModifierEvalContex
       numVerts, sizeof(*old_vert_arr), "old_vert_arr in solidify");
 
   uint *edge_users = NULL;
-  char *edge_order = NULL;
+  int *edge_order = NULL;
 
   float(*vert_nors)[3] = NULL;
   float(*poly_nors)[3] = NULL;