PR 3134

   PR 3134
   * h8300.h (h8_opcodes): Add an encoding for a mov.l instruction
   with a 32-bit displacement but without the top bit of the 4th byte
   set.

   * gas/h8300/pr3134.s: New test.
   * gas/h8300/pr3134.d: Expected disassembly
   * gas/h8300/h8300.exp: Run the new test.

   * gas/h8300/h8300-coff.exp: Fix test for COFF based ports to
   accept h8300-rtemscoff not just h8300-rtems.