[lworld] RFR: 8253724: [lworld] C1 compilation hits assert: Empty inline type access should be removed

[Frederic Parain]

Please review these changes fixing handling the handling of empty inline types in C1.
The changeset includes two new unit tests, but they are currently disabled because they are causing failures with C2
which has issues with empty inline types too (C2 will be fixed with a different patch).

Tested with Mach5, tiers 1 to 3.

Thank you,

Fred

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Commit messages:
 - Temporarily disable new tests
 - Fix handling of empty types
 - Handle empty inline types in withfield

Changes: https://git.openjdk.java.net/valhalla/pull/203/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=203&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253724
  Stats: 48 lines in 2 files changed: 45 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/203.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/203/head:pull/203

PR: https://git.openjdk.java.net/valhalla/pull/203