[code-reflection] RFR: [hat] Fix C99 codegen parenthesis when having inner iface interfaces

[Juan Fumero]

[hat] Fix C99 codegen parenthesis when having inner iface interfaces.

All supported test passing + violanes example.

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Commit messages:
 - [hat] Fix C99 codegen parenthesis when having inner iface interfaces

Changes: https://git.openjdk.org/babylon/pull/669/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=669&range=00
  Stats: 37 lines in 2 files changed: 29 ins; 4 del; 4 mod
  Patch: https://git.openjdk.org/babylon/pull/669.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/669/head:pull/669

PR: https://git.openjdk.org/babylon/pull/669