GraphChecker: Call VisitInstruction in VisitConstant

Fix some LSE gtests that were adding some instructions in
the entry block which don't belong there in normal graphs
(e.g. ArraySet, NewInstance)

Bug: 262862764
Fixes: 262862764
Test: art/test/testrunner/testrunner.py --host --64 --optimizing -b
Test: m test-art-host-gtest-art_compiler_tests64
Change-Id: I1ea4f3eaf79d4b98b441dcf89f73c7009a6fa9b4
2 files changed