[RFA] Remove some gcc xfails in derivation.exp

[Michael Elizabeth Chastain]

This patch is approved, provided that you update the copyright date
on line 1 of derivation.exp.

I checked my test logs and it's XPASS everywhere for me:

  native i686-pc-linux-gnu
  gcc 2.95.3, gcc 3.0.2, gcc HEAD, gcc-3_0-branch
  stabs+ and dwarf2

Michael C