Fixed stdout files for 'slow' mode.
Commit message says it all:
real/smallpt's .slowstdout file was missing.
The value in spectral/dom-lt's was wrong, also runtime was lower than 5 sek on my machine (should be between 5-10s), so I increased the argument and updated dom-lt.slowstdout. [was: ~4.9s, now: ~5.4s]