[code-reflection] RFR: Support array type constants in code model

[Hannes Greule]

Previously, expressions like `String[].class` weren't supported in the code model.

As types are embedded by their fully qualified names (e.g. `java.lang.String[]`), we also have to parse that representation again. I didn't find an existing method to do so, so I wrote it myself. Please let me know if there's a better approach.

I also adapted the test from `TestArrayCreation.java`, using different kinds of array types.

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Commit messages:
 - Support array type constants in code model

Changes: https://git.openjdk.org/babylon/pull/5/files
 Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=5&range=00
  Stats: 112 lines in 3 files changed: 109 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/babylon/pull/5.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/5/head:pull/5

PR: https://git.openjdk.org/babylon/pull/5