[code-reflection] RFR: Reduce number of local variables when transforming code model builder to AST [v2]

[Mourad Abbay]

> For CODE_BUILDER option, we transform code model builder to equivalent AST. We were introducing local variables for very expressions, as a result we were closer to the limit on local variables. In this PR, we add local variables where it's needed.

Mourad Abbay has updated the pull request incrementally with one additional commit since the last revision:

  Apply Paul's comments

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Changes:
  - all: https://git.openjdk.org/babylon/pull/410/files
  - new: https://git.openjdk.org/babylon/pull/410/files/cf8f38d9..f64ebf4f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=410&range=01
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=410&range=00-01

  Stats: 85 lines in 1 file changed: 4 ins; 67 del; 14 mod
  Patch: https://git.openjdk.org/babylon/pull/410.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/410/head:pull/410

PR: https://git.openjdk.org/babylon/pull/410