const testing.fuzzWorker

4 uses

	testing (current package)
		fuzz.go#L248: 	if f.fuzzContext.mode != fuzzWorker {
		fuzz.go#L375: 	case fuzzWorker:
		fuzz.go#L464: 	fuzzWorker
		fuzz.go#L545: 		fctx.mode = fuzzWorker