Use dwarf-to-dwarf-assembler.py on dw2-icc-opaque

I ran dwarf-to-dwarf-assembler.py on the output of the dw2-icc-opaque
test.  The test was already architecture-independent, but I think it's
a bit easier to read this way.

I made a couple of tiny edits to the output, that I don't think affect
the test:

* I slightly shortened the producer strings (removing the newline and
  subsequent text)
* I changed a DW_AT_data_member_location to be a constant rather than
  an expression