VerifyLoopOptimizations fails because split_if_with_blocks may introduces a new conI node.

it's one of problems causes JDK-8173709.
we observe error message like this:

Verify has that we do not: 172 ConI === 0 [[ 131 ]] #int:1
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/loopnode.cpp:3590
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/backup/skara/jdk/src/hotspot/share/opto/loopnode.cpp:3590), pid=21036, tid=21051
# assert(!fail) failed: loop body mismatch
#
# JRE version: OpenJDK Runtime Environment (16.0) (fastdebug build 16-internal+0-adhoc.ubuntu.jdk)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 16-internal+0-adhoc.ubuntu.jdk, mixed mode, sharing, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x116fd9a] IdealLoopTree::verify_tree(IdealLoopTree*, IdealLoopTree const*) const+0x62a