Fix self-testing of 32-bit or 64-bit shells in startjsfunfuzz.py.
Fix self-testing of 32-bit or 64-bit shells in startjsfunfuzz.py.

nth10sd/funfuzz,MozillaSecurity/funfuzz,MozillaSecurity/funfuzz,nth10sd/funfuzz,MozillaSecurity/funfuzz,nth10sd/funfuzz