computing whether instructions can be relaxed.
* ld-mn10300/i135409-4.s: New test case. Check for relaxation to a 16-bit
jump instruction.
* ld-mn10300/i135409-4.t: Linker script for the new test.
* ld-mn10300/i135409-4.d: Expected disassembly of new test.
* ld-mn10300/mn10300.exp: Run the new test.
