[code-reflection] Integrated: The OpWrapper removal caused a regression extracting nested ifaces

[Gary Frost]

This fixes a codegen bug where the lhs var assignment from a rhs iface buffer access was not generating the var decl ;)

This only affected violajones and heal examples.

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Commit messages:
 - The OpWrapper removal caused a regression extracting nested ifaces

Changes: https://git.openjdk.org/babylon/pull/550/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=550&range=00
  Stats: 4 lines in 3 files changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/babylon/pull/550.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/550/head:pull/550

PR: https://git.openjdk.org/babylon/pull/550