[lworld] RFR: 8250234: [lworld] [lw3] jdk/valhalla/valuetypes/SubstitutabilityTest.java fails with C1

[Frederic Parain]

Please review this small changes to fix a bug in C1 transformations which cause an acmp involving inline types to be
translated into a pointer comparison instead of a substitutability test. The patch also includes a few fixes in C1
debugging features.

Thank you.

Fred

-------------

Commit messages:
 - Renaming
 - Fix handling of substitutability tests during block merges

Changes: https://git.openjdk.java.net/valhalla/pull/128/files
 Webrev: https://webrevs.openjdk.java.net/valhalla/128/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8250234
  Stats: 18 lines in 4 files changed: 12 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/128.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/128/head:pull/128

PR: https://git.openjdk.java.net/valhalla/pull/128