[lworld] RFR: 8377809: [lworld] more incorrect execution due to EA pointer comparison optimization at scalarized call

[Roland Westrelin]

I realized my fix for JDK-8377480 doesn't work if a value passed as
argument is returned as `Object` (because then EA links the return
value with the `Object` field of the value passed as argument). It
doesn't do the optimal thing if the input value has multiple `Object`
inputs either. Anyway, I propose a conservative fix for now. I'll file
a bug to revisit that later.

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Commit messages:
 - whitespaces
 - more
 - undo
 - fix & test

Changes: https://git.openjdk.org/valhalla/pull/2094/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2094&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8377809
  Stats: 25 lines in 3 files changed: 21 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/valhalla/pull/2094.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2094/head:pull/2094

PR: https://git.openjdk.org/valhalla/pull/2094