[code-reflection] Integrated: More codegen tweaks

[Gary Frost]

Cleaned up codegen where we were generating 'raw' append(str) and emiText(str).

We should always call one of the methods in the TextRenderer iface. ... identifier,label,literal etc 

This helps when styling/colorizing

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Commit messages:
 - More codegen tweaks

Changes: https://git.openjdk.org/babylon/pull/562/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=562&range=00
  Stats: 243 lines in 8 files changed: 90 ins; 34 del; 119 mod
  Patch: https://git.openjdk.org/babylon/pull/562.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/562/head:pull/562

PR: https://git.openjdk.org/babylon/pull/562