1. check for dups in complex literals

1. check for dups in complex literals
   structtype{a:1, a:2}
   maptypetype{"xx":1, "xx":2}
   arraytypetype{5:1, 5:2}
2. bug in registerization concerning
   alias of a struct and one of its elements
3. code optimization of struct.field
   (which exposed bug in 2)

R=r
OCL=29315
CL=29315