Backout 8b2987b064a1, --enable-gccompacting is not a runtime flag, oops.
Backout 8b2987b064a1, --enable-gccompacting is not a runtime flag, oops.

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