ic: Fix denylist for IPv6 with same prefix length. #3430

Job	Run time
Prepare container	3m 7s
linux rpm fedora	6m 48s
osx clang --disable-ssl	2m 15s
linux gcc --disable-ssl	2m 33s
linux clang --disable-ssl	2m 40s
linux gcc test -300	9m 41s
linux gcc test 301-600	6m 53s
linux gcc test 601- unstable	6m 34s
linux clang test sanitizers -300	13m 25s
linux clang test sanitizers 301-600	9m 44s
linux clang test sanitizers 601- unstable	10m 56s
linux gcc test -ljemalloc -300	10m 3s
linux gcc test -ljemalloc 301-600	7m 22s
linux gcc test -ljemalloc 601- unstable	6m 39s
linux gcc system-test-dpdk dpdk -100	16m 50s
linux gcc system-test-dpdk dpdk 101- unstable	14m 35s
linux gcc system-test-userspace -100	16m 3s
linux gcc system-test-userspace 101- unstable	13m 34s
linux gcc system-test -100	18m 19s
linux gcc system-test 101- unstable	17m 42s
linux clang system-test sanitizers -100	20m 31s
linux clang system-test sanitizers 101- unstable	19m 37s
linux x86 gcc --disable-ssl	2m 31s
	3h 58m 22s

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