[lworld] RFR: 8370484: [lworld] PhaseOutput::FillLocArray asserts with Unexpected type: anyptr

[Tobias Hartmann]

[JDK-8366973](https://bugs.openjdk.org/browse/JDK-8366973) / https://github.com/openjdk/valhalla/pull/1554 added code to handle calls to a method with an unloaded return type. That code also changes the return type of the call to a scalarized return:
https://github.com/openjdk/valhalla/blob/a6d6cb8b9107cc6f8aeb28d5547cec9a5e58f711/src/hotspot/share/opto/graphKit.cpp#L2042-L2046

As a result, the old projection node still used in the "return is null" branch gets a bottom type which confuses code that generates the oop map. We should just use constant null there.

No regression test because basically all the serviceability tests fail with `-Xcomp`.

Thanks,
Tobias

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Commit messages:
 - 8370484: [lworld] PhaseOutput::FillLocArray asserts with Unexpected type: anyptr

Changes: https://git.openjdk.org/valhalla/pull/1714/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1714&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8370484
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1714.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1714/head:pull/1714

PR: https://git.openjdk.org/valhalla/pull/1714