[lworld] RFR: Make "PrimitiveParameterizedClass.default" a poly expression.

[Jesper Steen Møller]

Make .default a separate node type in the parser.

## Issue
[JDK-8211914](https://bugs.openjdk.java.net/browse/JDK-8211914): [lworld] Javac should support type inference for default value creation

Note: The Linux x86 builds in GitHub actions seem to fail with something completely unrelated to these changes.

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Commit messages:
 - Hmm, spaces
 - Make "PrimitiveParameterizedClass.default" a poly expression.

Changes: https://git.openjdk.java.net/valhalla/pull/369/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=369&range=00
  Stats: 317 lines in 20 files changed: 274 ins; 31 del; 12 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/369.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/369/head:pull/369

PR: https://git.openjdk.java.net/valhalla/pull/369