[smpi] replay from `smpirun -replay <tracefile>`

1. This commit changes the usage of smpirun for replaying traces.
- Removal of the -ext option
- Addition of the -replay <tracefile> option
- Addition of the smpirun ... -replay <tracefile> [program] [popt]
  syntax. It allows replaying without giving a specific replay program,
  but still allows previous behaviour by giving program.

2. This commit also updates the tests that were using the old smpirun
syntax.

3. This commit introduces a new `smpi-replay` test for smpirun -replay without
specifying a program. The old smpi-replay test has been renamed
smpi-replay-override-replayer