`LIRGenerator::do_ProfileACmpTypes` uses the wrong `maybe_null` property. Seems to be a copy&paste bug from the code above it. In addition, minor refactoring of the code generator for `opSubstitutabilityCheck`. RISCV has it already.
--------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - 8386598: [lworld] C1 acmp profiling fix and minor cleanup Changes: https://git.openjdk.org/valhalla/pull/2543/files Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2543&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8386598 Stats: 13 lines in 3 files changed: 4 ins; 8 del; 1 mod Patch: https://git.openjdk.org/valhalla/pull/2543.diff Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2543/head:pull/2543 PR: https://git.openjdk.org/valhalla/pull/2543
