Please add qemu mode support for ijon

[nj00001]

In the latest aflpp dev branch , afl_fsrv_start func, the qemu status variable is much larger than 0x41464c00, which makes it impossible to determine the FS_OPT_IJON flag

Referring to the following screenshot, the judgment of the ijon flag seems to be only in the source code instrumentation, but qemu may support ijon, so can this flag be placed in a more outer layer?

[vanhauser-thc]

ah yes, qemu mode still uses the old forkserver.
you will need to upgrade the forkserver code in qemu.