[lworld] RFR: 8255045: [lworld] LoadNode::Value() use of markWord::prototype() may strip type bits

[Tobias Hartmann]

`LoadNode::Value` detects mark word loads and replaces them by `markWord::prototype()` which would strip inline/flat/null-free property bits. We need to use the prototype header from the klass. When writing tests, I've found an independent problem (due to a typo) in `Parse::do_monitor_enter()`.

Best regards,
Tobias

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Commit messages:
 - 8255045: [lworld] LoadNode::Value() use of markWord::prototype() may strip type bits

Changes: https://git.openjdk.java.net/valhalla/pull/337/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=337&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255045
  Stats: 100 lines in 6 files changed: 96 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/337.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/337/head:pull/337

PR: https://git.openjdk.java.net/valhalla/pull/337