Remove unused code for setting gczeal through prefs. Since rev fc0df8c2f2bb, the content script has used getJSTestingFunctions instead.
Remove unused code for setting gczeal through prefs. Since rev fc0df8c2f2bb, the content script has used getJSTestingFunctions instead.

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