Fix ReplacementOrValue() for Partial LSE.

Also fix a bad DCHECK() in `FindSubstiute()` and fix the
HeapLocationCollector::VisitPredicatedInstanceFieldGet()
to use the correct input.

Test: New tests in load_store_elimination_test.
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 188188275
Change-Id: Ifdace5ddbe1777af2109189013c0557f226d9cc9
3 files changed