[lworld] RFR: 8258480: [lworld] Adapter creation asserts with -XX:+VerifyAdapterSharing

[Tobias Hartmann]

`VerifyAdapterSharing` fails because the code of two adapters with the same fingerprint is not equal. The problem is that we are accidentally creating an "only unpack receiver" c2i adapter for a static method with an inline type as only argument. As a result, the special handling in sharedRuntime.cpp:2446 does not work.

I've also refactored related code and fixed a test bug.

Thanks,
Tobias

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Commit messages:
 - 8258480: [lworld] Adapter creation asserts with -XX:+VerifyAdapterSharing

Changes: https://git.openjdk.java.net/valhalla/pull/304/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=304&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8258480
  Stats: 43 lines in 3 files changed: 6 ins; 14 del; 23 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/304.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/304/head:pull/304

PR: https://git.openjdk.java.net/valhalla/pull/304