[code-reflection] RFR: Concat Transform Optimizations [v3]

[Ian Graves]

> Updates to the transformation on Concats to StringBuilder that reduce redundant "new" StringBuilders while respecting correctness.

Ian Graves has updated the pull request incrementally with one additional commit since the last revision:

  Updates to cover additional tests and types

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Changes:
  - all: https://git.openjdk.org/babylon/pull/149/files
  - new: https://git.openjdk.org/babylon/pull/149/files/2cfe4dea..0ae8001e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=149&range=02
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=149&range=01-02

  Stats: 131 lines in 2 files changed: 109 ins; 2 del; 20 mod
  Patch: https://git.openjdk.org/babylon/pull/149.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/149/head:pull/149

PR: https://git.openjdk.org/babylon/pull/149