On the i386, load the ELF dynamic linker where an mmap(0, ...) would

On the i386, load the ELF dynamic linker where an mmap(0, ...) would
put it, just like on the Alpha.  It was wrong to load it at the
fixed address 0x08000000.  That should only be done if the dynamic
linker is an executable (not a shared object) with a specific load
address encoded in the object file itself.

This fixes the recent breakage in the Linux emulator.